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Lecture 11. More Reactions of Enols and Enolates.

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Lecture 11. More Reactions of Enols and Enolates.
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This is the third quarter course in the organic chemistry series. Topics covered include: Fundamental concepts relating to carbon compounds with emphasis on structural theory and the nature of chemical bonding, stereochemistry, reaction mechanisms, and spectroscopic, physical, and chemical properties of the principal classes of carbon compounds. Index of Topics: 1:05-Enolates 3:57-Enolates and Electrophiles 9:11-Alpha-Halogenation of Ketones and Aldehydes 13:58-Halogenation Mechanism 21:58-Halogenation Example 25:10-Alpha-Halogenation Promoted by Base 35:29-Haloform Reaction 39:02-Haloform Reaction Mechanism 43:37-pKa Values 53:20-Reason for Acidity 1:00:35-AcetoAcetic Ester Synthesis 1:10:36-Malonic Ester Synthesis 1:14:44-Example Problem
reactive Lecture/Conference carbon chemische Reaktion chemical man
sense sodium hydride species Mesomerie Carbonyl Compounds chemical Table wine Säuren electron Lecture/Conference Enolates Generic drug coupling compounds chemical structures basic form
concentration Highway Addressable Remote Transducer Protocol chemische Reaktion solutions alcohols man reactive Hydration water Zearalenone Säuren Lecture/Conference sulfuric acid
near sense hydrogen bonding Glycosaminoglycans chemische Reaktion chlorine chemical end reactive molecule Muraminsäure Magnetometer Lecture/Conference Hydroformylierung Brom Halogene
reactive conditions Säuren nitrogen Lecture/Conference Double bond Alkyl Halides carbon Ethylen-Vinylacetat-Copolymere chemische Reaktion Electronegativity man
reactive conditions Lecture/Conference media oxygen form stability man
van Muraminsäure Lecture/Conference Alkyl Halides Methyliodid rates alkyl Glycosaminoglycans chemische Reaktion Halogene man
Ester conditions Weinfehler Lecture/Conference chemische Reaktion chemical end man
balance Ethylen-Vinylacetat-Copolymere proton chemische Reaktion chlorine man variety reactive Säuren Lecture/Conference Altbier Brom Hydrogen Halides chemist
reactor sodium hydride Maische chemische Reaktion Hydrogen Cyanide chemical man Trihalomethane van Magnetometer Lecture/Conference Sieden condensation
chemische Reaktion Electronegativity chlorine Hydrogen Cyanide man water Säuren Lecture/Conference Gamma conjugate period methanol stuff
Alpha water lone pairs electron Prolin Magnetometer Lecture/Conference mechanism steps proton man
Double bond carbon chlorine man Alpha flow lone pairs Wasserstoff Säuren electron Lecture/Conference Gamma compounds oxygen
steps chloride proton chemische Reaktion chlorine firm man lone pairs water Säuren conditions electron Lecture/Conference Gamma Alu element storage basic oxygen
Magnetometer Lecture/Conference Double bond Maische cell chlorine chemical man
Grease interceptor chloride hydroxyl groups carbon additional Terephthalsäure chemische Reaktion case chlorine Iodide Magnetometer Lecture/Conference compounds chemical structures
type Double bond steps proton chemische Reaktion case chlorine chemical man water Säuren electron Lecture/Conference coupling basic oxygen
water Disproportionierung Säuren Lecture/Conference Gases Superacid remove Salzsäure Brom solutions chlorine
Geochemistry rates steps gene chemische Reaktion methyl chemical variety water Eisfläche Säuren solvents Lecture/Conference function Brom period form methanol
alkyl carbon operation Carbonyl Compounds chemische Reaktion chemical orbitals reactive Lecture/Conference function compounds standards form
organizations LSD Bromide balance proton chemische Reaktion source chemical OH- man reactive Alpha chemical equilibria water Lecture/Conference control Brom basic Halogene
Alpha flow electron Arginine Lecture/Conference mechanism Double bond Heroin carbon Brom proton oxygen
progress Säuren electron Lecture/Conference Double bond important Mesomerie chemical structures carbon oxygen conjugate processes
Bromide Gletscherzunge chemische Reaktion OH- chemical man water Zeitverschiebung Säuren metabolic pathway Lecture/Conference basic conjugate
organizations nitrogen KOH proton chemische Reaktion chemical OH- man Alpha Natrium Natriumhydroxid Lecture/Conference important compounds Common Brom bottles silver
Stop molecule Säuren Lecture/Conference compounds Brom basic proton chemische Reaktion man
organizations Lecture/Conference control chemische Reaktion end
power bond Natriumhydroxid Lecture/Conference Brom mixture Gletscherzunge Carboxylierung chemische Reaktion form chemical man
molecular van Natriumhydroxid Lecture/Conference KOH Brom gene basic chemische Reaktion chip chlorine
precipitation bond chemische Reaktion gold methyl chemical man Alpha van Drops Natriumhydroxid Lecture/Conference Generic drug tube compounds remove Methylmalonyl-CoA-Mutase form Halogene
Digital elevation model Klinisches Experiment Zearalenone conditions electron Lecture/Conference Brown adipose tissue alkyl carbon chemische Reaktion OH-
metals organizations mechanism methyl firm stability Zearalenone electron Lecture/Conference function Brown adipose tissue covalent Methylmalonyl-CoA-Mutase Carboxylierung lithium Satellite DNA
Lecture/Conference factors Stickstofffixierung steps carbon proton Carboxylierung chemical
type Cyanide carbon Sodium cyanide chemische Reaktion man lone pairs Zearalenone conditions electron Lecture/Conference conjugate bottles
Cyanide type Lecture/Conference Methane van chemische Reaktion source radiation form period chlorine methyl
Polyurethane factors Chloroform carbon source man chemische Reaktion Ästuar chemical water Tonmineral Lecture/Conference markers pKa form period
type bond rates kinetics chemische Reaktion methyl chemical man conditions Lecture/Conference Butyric acid basic period Halogene
biosynthesis alkyl chemische Reaktion source chemical Müllerin Säuren Lecture/Conference compounds aspirin remove chemical structures scale Carboxylierung lithium
Pentane Färben Wasserstoff Säuren Lecture/Conference function compounds remove Carbonyl Compounds source fish
Diet food Acetal Zeitverschiebung mixture Magnetometer Arginine Lecture/Conference function yield carbon Carbonyl Compounds source
Mesomerie spread paintings alcohols stability lone pairs Natrium Lake Säuren electron Natriumhydroxid Lecture/Conference Wasserbilanz compounds localization remove chemical structures oxygen Carboxylierung
Acetal Mesomerie electron donor des carbon source man water Ethanol Natrium Säuren Natriumhydroxid Lecture/Conference orders of magnitude Altbier pKa remove chemical structures oxygen Tillit
Acetal biosynthesis Tactics Ester Bohr Gases proton chemische Reaktion chemical OH- man Natrium Säuren Natriumhydroxid Lecture/Conference Carboxylierung mixture Oxide den oxidation
Trihalomethane metals Acetal Magnetometer Lecture/Conference compounds Methylmalonyl-CoA-Mutase chemische Reaktion Medroxyprogesterone extract man
Drink Ester mechanism Bromide Alkyl Halides glass Gases chemische Reaktion man Ethanol Natrium Säuren firing Lecture/Conference Scotch (band) Oxide methanol stuff
metals areas Acetal sodium hydride Bromide Alkyl Halides alkyl steps chloride chemische Reaktion Concretion man Ethanol water Natrium age Lecture/Conference Gamma sulfuric acid bottles
Alpha flow electron Gastrin Lecture/Conference steps carbon chemical structures Brom man
Färben Eau de Cologne mechanism Bromide steps water Ethanol Heck Reactions Säuren Lecture/Conference function shot hydrolytic Applikation <Medizin> Zigarre Carboxylierung
molecule Wasserstoff bond electron Lecture/Conference Double bond hydroxyl groups carbon Carbon dioxide oxygen
bond electron Lecture/Conference Carbon dioxide Carboxylierung chemische Reaktion
Ethanol synthetic Natrium Lecture/Conference alkyl methyl chemical man
metals biosynthesis Lecture/Conference function Methyliodid carboxyl group alkyl Carboxylierung chemische Reaktion chemical man
Trihalomethane Färben Acetal Ethanol type Lecture/Conference Alkyl Halides Carboxylierung chemische Reaktion slides chemical man
Färben Alkyl Groups Halides Bromide Alkyl Halides Maische Grus Gases immune cell Stickstofffixierung asset hydrogen bonding Taxis chemische Reaktion case chemical man Säuren electron Lecture/Conference function Tamoxifen Carboxylierung alkali
sense type synthetic biosynthesis mixture connection Lecture/Conference Maische fine Bis (band) alcohols end
Alpha biosynthesis bond Lecture/Conference Maische Essenz <Lebensmittel> compounds Beta carbon chemische Reaktion chemical
type bond Halides Bromide chloride chemical man Trihalomethane Diet food Ethanol Natrium van Lecture/Conference Medroxyprogesterone remove processes
Acetal bond biosynthesis Anorganische Chemie paintings Salzsäure proton chemische Reaktion man water Ethanol Lecture/Conference Gasoline orders of magnitude compounds sulfuric acid Stream bed Carboxylierung Spektroelektrochemie Oxide
Diet food biosynthesis Table wine Säuren Lecture/Conference Methyliodid steps basic chemische Reaktion
Ethanol Natrium probe Lecture/Conference Peroxyacetylnitrat steps active site basic Carboxylierung oxidation stuff man
Mauritania was so today I'd like to
continue our discussion of carbon chemistry and
remember we have now started on this 2nd aspect of carbon chemistry reactivity of the Alford carbon and so for this lecture and then the following 2 lectures were going to continue to be developing this idea so today
we're going to discuss a few more reactions of the Knowlson evil lights and what we do today is going to set the stage for a Chapter 20 forcible be finishing up Chapter 23 and setting the stage for Chapter 24 which really gets into some absolutely beautiful and profound carbon Hill chemistry with the Algol reaction and the Clayson our reaction so I wanted to start out just
by by coming back to to 18 also need In so here is sort of a generic structure of any and all maybe all
drawn a couple of long pairs of electrons just so we get a nice nice resonance structure and here is a generic structure of Indiana late Of course he
knows we've already talked about in the sense that we've said they're not stable species that you can isolate in in general that while some compounds are largely and all like most carbonyl compounds have only a tiny percentage of Renault that forms at any given moment moment and it's transient formed
business acid or base catalyzed lights on the other hand we've already seen with sailed a chemistry that you can go ahead and quantitatively converted the tone to any late by treatment with LDA
so if I want to make some generalizations because we're going to be talking about principles of reactivity both today and then in the next 2 lectures if I wanted to talk about some generalizations
I'd say that laws are more reactive than Al teens In other words we've seen
acid promoted reactions have been also we were seeing taught time reservation in these reactions occur with very mild acid you've seen reactions of Al Qaim so for example you've seen treatment of an Al-Qaeda like I said Beuerlein with a quiz sulfuric acid to former hydrate out to form an alcohol the hydration the addition of water across a mail came with by way of a cobbled cattle and that
requires a very strong acid typically typically you're talking about taking NL team with a concentrated sulfuric acid solution where is in the
chemistry of the malls with Electra files because you're getting an Oxo Cobby near on intermediate not regular cobbled Qatar and that really is suffering from a lack of a complete architect you
have a much greater propensity to react with Electra files so if I wanted to can if I wanted to sort of characterizing I'd say it reacts with very reactive Electra files but it the end that sort of sort of our a relative term in the sense that Al Keane's react with even require even more reactive electrified react so
we're going to see reaction with halogen I'll just write this as exit to indicate really chlorine and bromine riding foreign so we sinister special category will react but react with absolutely everything because the flooring you know every position in the molecule because the foreign hydrogen bond is so strong so I'll
Keane's also react with diligence but now where you start to see enhanced reactivity is for example protonated carbon meals typically if you hadn't tone and answered sure you generate a protonated carbon Neil transient but it's not going to react with a typical haloalkane under typical conditions again I can give you exceptions to that whereas this is going to be the basis
for what will see in the next lecture on the acid catalyzed Algol reaction although I won't show examples were not going to talk in detail about the chemistry of give you
1 sort of comparison if we talk about in Amenia minor so the US sort of many mine
intermediate we talked about before these 2 0 react within also in what's called the manic reaction remember how I've talked about the Algol I've
talked about carbon-oxygen double bonds and said in many ways carbon nitrogen double bonds are very similar in their reactivity so an evening is very similar to achieve tone in its reactivity just a little bit less so because nitrogen is a little bit less selective felt like a little bit less like negatives
in a medium ion is very similar to approach needed Tetonia and so there's this manifold of reactivity worth a typical wouldn't under
usual conditions react within the monument corporate needed tells now coming to penalize since we now here why is this more
reactive you've got the oxygen pushing electron density into the being double bonds so you're donating an electron density it's more electron rich then a regular AL teams and kind and along the same
lines as I said when it reacts with Electra files the Carbol Qatar and that forms gets extra stabilization from that oxygen well penal lights are even more nucleophilic in other words the even more reactive toward electoral files so
in addition to things that are only moderately Elektra fell like a very alike are in addition to things that are very reactive Elektra files feel lights can react with moderately reactive electoral files so sure anymore
late will react with a halogen because
halogen served good really good electrify also but you can also react with things like alkyl halide skin as central reactions we saw this before when we talked about the direct alkylation Avino
lights taking Tetonia converting it to being a light with LDA and then I'll collating it's a with methyl iodide as we saw in the last lecture G
Townsend Alger hides her a lot less reactive and protonated tones it now the hides and so these 2 0 react with an e-mail light because new light is so much more electron rates so much more
nucleophilic then again this is chemistry will be picking up on in Chapter 24 when
we start to talk about the Algol reaction and then summarily under the right conditions esters which are even a little less reactive and tones and a good bit less reactive the hides also under the right conditions can react with the analysts are right where I'd like to begin today's discussion talk
about reactions with diligence so specifically the outfit intonation of the tones and held a high at the
end so sort of very generic equation if I have some sort of Quito morale the hide the but obviously
with Alpha protons and weak treated with some halogen and as I said before we're really talking chlorine and bromine variety being with sort of being in a special class of its own and reactivity you react together now for Hello Keatonâ elder hide inorganic
chemists terribly bad balancing equations but also hydrogen halide Mississippi this is important the
reaction in the acid manifold all manifold is catalyzed by AST said it's right reaction of proceeds
fighting all of now a reaction produces its own catalyst that means the reaction is also auto catalytic itself
catalytic it caramelizes but auto
catalytic reactions can be a lot of fun because often that means you mix the reactants and they seem to just be sitting there and then they start to reactor because you have a little bit of the acid around
the war because it can go by and on catalyze manifold are you always have some mean all present so it generates more catalysts which goes faster and faster and faster and if you don't have it benefits exit there makes it can take off because with more heat that it's producing it'll go even faster and produce more catalysts which is 1 of the reasons why when you're in the
laboratory here so often running reactions insolvent rather than mixing chemicals directly together the solvent dissipates the heated can boil With a reflux condenser and be convinced and come back and take away the anyway so for example all right all right a real example of a reaction if you take cyclone
taxonomic sin treated with chlorine in water so often when writing synthetic reactions will just write reagent over the and sometimes solvent below the arrow then you get me out coral
cyclone known to cyclo Hexham known in right plus 8 Cl although remind us that when were in water of course you don't have a DSI and water when you're in
methanol you don't have a DSI Allen methanol because you program a yourself and you probably make your water to give Heidrun EMI and HCL is a much stronger acids negative PKK of negative Severna there abouts too much stronger acid than the conjugate acid of
water at the hydrangea minded ditto for methanol stuff I really wonder wanna write things down here I'd say .period stage Rio Plus In CEO minus so let's take a look at how this reaction occurs Arafat we talked about utilization last time so I'm
only going to ride out a sort of abbreviated mechanism that will not write every last lone pair of electrons in writing my mechanism I will not right every step in gory detail so for example Archie tone was H 3 0 plus there's going to be an equilibrium with the pro dated Tony In water water can pull off
the alpha proton you've seen all of this mechanistic and so you have this equilibrium deformed all remember that equilibrium
lies wait wait to the left so you only have a teeny tiny percentage of the being only a fraction of a fraction of a per cent of in all at equilibrium but that's OK because it's going to keep getting regenerated under the
acid catalysis as soon as you use it up so our are being also is nucleophilic than the alpha carbon here's our
chlorine I won't draw all the lone pairs of electrons on the chlorine but electrons flow from the oxygen down the flow from the double bond to the chlorine we push electronic
break the chlorine chlorine violence push electrons onto chlorine and nail you
get the Alpha coral compound and I'm only going to remind us here that we have a
hydrogen at the Alpha position just to help us keep track so I suppose if you wanted to you could go ahead
and put in a hydrogen here I just don't want to lose track
of what's connected to what carbon and the other thing that's produces chloride and like
again I'm not going to
ride in every lone pair of electrons then in the next step we're going to just lose our Proton and remember technically although chlorides evasive urine water reaction like this would be done literally bubbling chlorine into water bubbling chlorine from a gas
tank into water to make or rainwater and so if you're in water the the strongest base so that you'll have is water under acidic conditions and so we can envision the water
coming along with its lone pair of electrons falling off a proton putting them back putting electrons back
onto the fruit needed
oxygen in guess I guess here if I want to be a good person actually I am going to say
this 1 is essentially irreversible because basically wants to form that chlorine bombs you are for all intents and purposes not breaking it again so our
overall outcome but it is now you have the alphabetical Roebke plus 8 3 0
question the only 1 in the last year up OK to have a good
question so the question that's being honest is we have chlorine here and we have Balanchine and we have a
lot of that with chlorine you can added crossed the double bonds like so don't worry about your stereo chemistry right now civil learned that you can do that and indeed it's
possible that caloric chlorine because you think of it as stepwise you have that 10 IOC Sykora being mile on you
can write the other residents structure just like you do with an disable chloride could come in intercept and indeed it could and indeed it can do we have any ideas about what this compound would do take out
the guy leaving there were actually gonna come back so engaged so sure chlorine could
add as an equilibrium and you're never going to have a stable harder of chlorine into the carbon meals whether it's as a Nazi or as a hydroxy Corrow compound were going to come back to to this idea when we talk about the Hill a former reaction which is a really weird reaction will talk about that in a moment but talk about it in a little bit but you never ever stable additives like 1 exception of iodide can adding to acetone and certainty tones and form a stable Oxy and iron out actor book doesn't mention it it's sort of the exception they said never occurs and give you the 1 exception questions are OK these Djokovic the ones next to it how funny either side in this case are equivalent and so you basically coordinate once if I keep pushing it and letting
it go longer yodel chlorinated again but this reaction pretty much because the coroner's electron withdrawing can stand up very nicely after
addition of 1 chlorine I'll show you an example in a moment where we have 2 different ones will talk about the Riccio of chemistry How does the double bond forming the 1st step over here how does that get there in other words how do we get from here to here told him
so interior protons waters your strongest base can think of water looks as pulling off of
protons electrons flowing the electrons flow onto the oxygen you're welcome so that's that's acid catalyzed formation alright so
let us talk now about some other cases of getting a couple of examples now 1
thing that I have done is broke with your text book and I know you get bent out of shape when I tell you the way things really work and you text but gives you slightly simplified answers so I draw any catalytic acid in there and in reality you really don't need it now tell you the secret about chlorine chlorine in water so not only do you have some you know all get things going but chlorine actually disproportionate dates and water giving HCl hydrochloric acid
and HOC L hyper chorus acid so a solution of chlorine water is always acidic so you
don't need to add any acid to get things going on in example straight from your textbook of it gets you last bent out of shape would take acetone and treated with bromine and as I said this really works for all of the 3 regular intelligence take acetone trader with bromine and acidic gasses and you get Alpha Brownlow acetone plus a B or and by the way in which we are in a seedy gas at is super super acidic because city gas is less basic and water sewage br Inesita gas it is
really strong you're getting a lot more acidity than that 1 .period negative 1 . 7 of 8 3 0 plus anyway I'll give you another example and come back to the question of real geochemistry 1 of the things that's cool about this reaction is the
rate determining step is the normalization as soon as you forming all it's consumed by your Meligeni does and it's irreversible hence my my writing my my arrow like that so the gene all that forms more quickly is the last
substituted in all we talked before about being lights and we describe kinetic lights the last substituted in the late and thermodynamic Tina like the 1 that's more thermal dynamically stable the more substituting light what's kind of the same within also when you don't
have to different groups like an ice probable group and a methyl groups then you end up going at the last substituted position and again this chemistry works in a variety of solvents or just give you another 1 bromine and in methanol you notice all of these appropriate solvent water a CD gas and methanol typically goes to the solvents that promoting normalization and so those are the solvents typically 1 would do this chemistry and so then
we go through that the more kinetically favorable he in all
and as soon as in all forms its consume we get the last substitute compounds don't get to bent out of shape over these details isn't so much of the chemistry I can give you there are many many layers that gets deeper and richer you can go on and on and on with it but I wanted to give us a flavor mechanistic and give us a flavor synthetically health Hello carbonyl compounds are really cool your textbook talks a little bit about their reactivity they're really good out collating agents innocent to alkylation kind of like a little like conventional like a light switch or more reactive toward into alkylation toward us into reaction than a standard operating agent has to do with the orbitals on the carbon you with you orbitals of the bends over Group anyway a textbook gives you some nice examples including talking about
synthesizing LSD what I'd like to do now is to talk about how Alfred intonation promoted by basis I'm not saying catalyzed because you'll
see when I balance my equation that we use up Homola equivalent of base synthetically This is the last useful reaction and remember organic chemist tend to be control freaks we like to control reactions and make them do what we wanted synthetic laid off and evil like chemistry ends up being a little less controlled in the halogen manifold in
the hill intonation manifold so let me start with a simple example which is controlled and I'm sort of
writing some of these examples around your text books just to keep things in line with this and to illustrate a few principles of reactivity so let's imagine that we have this penalty tone so we have 1 alpha proton and we have a source of base so we can form the inner light in an equilibrium reaction remember the PKK of a typical owners is about 20 this appeal more acidic but generally that means since water the PKK applied for water deep wrote mating is 15 . 7 you're going to have an equilibrium reaction anyway plus bromine and so very much like the other chemistry we were talking about your going to end up Alpha brominated and if I write a balanced equation you'll see that the other products of this reaction plus bromide ion and plus the water she had noticed we've actually consumed Imola equivalent of hydroxide in the region in the reaction of the chemistry is very similar to inner light nucleophilic the light is even more nucleophilic then again I'll skip over the curb
mechanism for reforming the delighted just pulling off the alpha proton and pushing electrons off onto the oxygen so I'll just write it in shorthand as a minus over the arrow to give us the
corresponding in late and now we have our
bromine and again all right things in a little bit of shorthand riding the bromine over the heroine's stiffing writing every bloody last long pair of electrons electrons flow from
down from the oxygen to give us a carbon Neil Back and over the from the double bond to the bromine and push electrons onto the bromine to give
rise to the Alpha Bromo Keaton was from either of them
remember if you're uncomfortable with all of these arrows moving at once remember that picture in your mind of the 2 residents structures of the
evil like the 1 with the negative charge on the oxygen and the other with the negative charge on the carbon and I said I'll usually just Stevie 1 in my mind and it'll be the more important
the bigger contributing residents structure this residents structure but what I'm really doing with this harrowing moving the electrons from the double bond of course is just the mental process of getting to that other resonance structure so if you're uncomfortable with that just think about the residents structure like so it certainly is more intuitive but Johnny probably for example would never never right this is the attacking resonance structure just because we tend to think about it the more important resonant structure question it was the right would bromine minus the progress made another good question in general equilibrium tend to be active tend to the significant within about 10 PKK units HBO are various said conjugate acid a worldwide about negative a negative 9 somewhere around there bromides not going to deeper wrote made
significantly more water speaking of the conjugate acid negative 1 .
7 not going too deep wrote made significantly so if you really we ran out of hydroxide slip into the acid catalyzed manifold if I tried to play a trick on this chemistry and use have been equivalent of hydroxide and a full Moeller equivalent of bromide I suppose the 1st
half of the reaction would run in the base promoted manifold and then as the base with was consumed eventually we'd start going through the normal path where I've never tried it these are good questions I like this is a lot more fun than simply
babbling on I'm means your mind is working and lower hadn't happened next class we all
get downward toward the front row what's there is no fun in being in the
Vaccarello far-right
itself let's continue with this because I wanted wanted take Gustason principles and something that's whole kind of counterintuitive no
longer Silver important in terms of analytical chemistry but nevertheless very cool alright now let's imagine because I'm gonna walk past from something where we have 1 hell of a Proton something where we have to allow for protons and then to a compound where we have 3 Alpha protons all on the same problem so
let's imagine we take this city manifold but based any notice IV remember I make this
point you can't go to the stockroom Indiana bottle of hydroxide the look at you funny about which I got idea what potassium hydroxide sodium hydroxide usually organic chemists will use 1 of those 2 sodium is common rights alternate sodium hydroxide and bromine shall indicate excess fluoride and didn't do it all right access rather than the word excesses are not right he doing I think you're textbook rights excess EXE ESS we also in the laboratories when our gas tanks get empty from nitrogen we run reactions under them right Emma T on the gas tank in
shock alright so we get the diagram of compound now the real thing I wanna make is not required make some noise from life the real
thing I wonder wanna say it is the reaction doesn't stop at the monitor remote from him no other words what I'm saying is if I wanted to make the monolog Romo compound by this
route I'd be in trouble like I want to make them on a program of combat we could go in the acid catalyzed manifold but if I wanted to use the base town of catalyze manifold I'd be in trouble if the problem
is electron withdrawing and so once you put 1 bromine on their 1 studying has reacted once and we get approach that we get a
bromine on there now this protons more acidic and so you get this competition now you've got this molecule part way through the reaction you got this molecule with 2 protons that are less acidic and then the molecule with the bromine with the bromine next the proton making it more acidic so if I wanted to be a troublemaker and say
If you go ahead and use 1 equivalent of so right in a OH the yard to 1 equivalent the Q U I the meaning equivalent and see what happened then I'd end up with a mixture of
products might end up with some of the died Bromo I haven't done this myself but better be called the Monitor abide by in America's you'd see peace for all of these are some of the UN reacted starting material you'd probably see some of the Amano Bromo in there as
well but and that's fine it's cool it's it's
OK but remember what I said before about organic chemist being control freaks typically we wanna take reacted and converted to a single product and so from the point of view of carrying out a synthetic reaction it's not so useful it's not
so helpful To be able to get a mixture of power or do not be able to get a single product better to do it in of catalyze manifold and it Our somewhere all of this is leading somewhere in front the chemistry so let's
take the example now where we have 3 Alpha 4 Proton so instead of Popeye ofa known or ISO Buturo often on the first one we had will take a seat Nolan and let's make our lives simple will treat those with sodium hydroxide and bromine and again all right access and now what's really wild is we break carbon-carbon bonds can we get the carboxyl late in CHP or 3 which we call brought which is called Romo form and this reaction is general that works with
all 3 of the main intelligence chlorine bromine and iodine all the important ones and so this is called the hell of warm reaction so in other words I can write its general for Mattel Teton so
I can write this sort of in general terms followed a medical key town drawn sort of generic away with L 2 they are too the more I to in other words molecular chlorine bromine or I gene and some base of sodium hydroxide
but again potassium hydroxide would do just fine generates well minus Aurora CO 2 -minus depending on how you prefer to write it neither of them is fine
plus the CHC all 3 or 4 CH br 3 we already
said that Romo forms also a plus 1 or the other works ch finds 3 I order form it's
historically this reaction is being
used as a chemical test for methyl Tetons nowadays if you wanted it to methyl Tito wildest taken on a Moran OK you've got a methyl peak and you've got a key
tone in the eye on the methyl peaks at about 2 parts per million is Sabah Mathilde fetal but historically this was used as a test and typically it was done without hiding because I form is really cool it's the yellow organic compound so you take a Mathilde Tito like acetone a drop of it a test tube with some sodium hydroxide and you throw an idea this yellow precipitate comes out which is really cool so you've got this chemical tests and only occurs with Mathilde the tones
I order forms also needed to get this really need over to it it's got his characteristic smell very really pretty however the thing and I want text presented this this is a reaction that historically I thought not do I really want to teach this to stop words it's counterintuitive it's actually cool and it's counterintuitive news and it also is relevant and so I do think this is worth worth learning about so what's going on in this chemistry were breaking of carbon-carbon bonds so there's something weird going on here so I'm gonna start was not a sort of are generic Mathilde Quito like snow and I'll say it has evolved by as above of course I mean for informed you laid out for generate million late again Alpha halogen again form immolate once again outfit halogen once again and so will that this point we
have the trial Hello
Mathilde this is unstable pervasive and that's really the key it's unstable under the reaction conditions it breaks down we now put the story electron withdrawing hell legends on carbon even know it's an alkyl carbon it's getting to be a very unusual alkyl carbon it's rendering by pulling electron density away from the Carbondale it's rendering the Carbondale more Elektra fell like you've got hydroxide present itself here's our hydroxide hydroxide can adding that within in a few electrons and try to be a good person hydroxide now adds a into this extra Elektra felt like carbon now here's where things get fun you only draw at the lone pairs of that we need just to prevent us from going crazy here
alright so at this point we formed a chapter here all intermediate but what special here is that that try Hello methyl group is electron withdrawing unlike say a methyl group Boren Alco group in general he can stabilize electron density so here's the big surprise electrons come in and they push it out like a leaving group because indeed it has a leaving in this
particular context so electrons come back we go ahead we end up with a
carboxyl like an and again on drawing abbreviated mechanism I'm not putting in regards daughter-in-law parable electrons are cops
and here's the kicker ,comma ban and we don't normally say Ka-band you see a satellite and I'm but normally I mean we see a growing yard a Cedergren yards like car Ka-band but you really have a covalent bond to the metal you can just think of it as being like that called for about an hour because the metals elect positive or dental lithium reagents same thing about organic lithium like pure lithium is a white the bureau and I was not really a Buell and but here we can kick out a car and there's something special so I'm gonna write exclamation
point just have to bring home the point and of course the combat ideas so basic so it can pick up a proton carboxyl I guess it's the most acidic thing around and so we have the carboxyl attested floss are
helpful but were dancing around this very uncomfortable step here we're dancing around this factor that I just picked out a carbon with a negative charge on us now you've seen this before you've seen this before you've seen this insight and a hydrant chemistry where are we now that we inform us and Ohio but we also know under basic
conditions the scion a hybrid formation is reversible and so on inside an Ohio
information we learned it forward and backward we encountered on the way it we became comfortable with the idea of taking out cyanide on and
getting a carbon Neil back again and just
drawing in the relevant lone pairs of electrons and the key on this of course was that well cyanide adds a negative charge on carbon black it's special 1 million go you can buy a bottle of sodium cyanide ACN right we always talk about how stable in Anaheim is by thinking about the PKK of the conjugate answered 8 CNS has a PGA of about 7 . 9 so what's going on here in the hell of warm reactions well chloroform as a PGA of about 25 textbook uses that
number that's the number I used to so when we take out the try coral
methyl have it's not like a car back and remember methane is 58 this is much more like a stabilized .period van I'm not as good as cyanide I was curious because I didn't have the numbers at my fingertips I wouldn't expect you to be there but the care for Bromo form is about 23 off of at least 1 source and I O the former hygiene is more polarized emboldened chlorine even know it's a less Elektra negative that means can better stabilize the unusual chill they to mean approximately 10 better stabilize the negative charge decay of 14 said the ion of former reaction the 1 that you can do when attests to really really works very easily because basically here kicking
out something that's kind of like an inside a hydrant formation
now what's called upon made about this chemistry here we always calibrate ourselves I emphasize this idea PKA and water markers staff have in your head for
various values sigh said a factor of 10 10 PKK units is sort of my waiting on whether an equilibrium occurs to any significant extent and take
away that for kicking out man I had out of a carbon meal that that 24 lives sort of is that teetering edge .period Now this is going to come back in Chapter 24 when we discussed the clays and reaction but more specifically when we discuss its mechanistic reverse the clays and reaction involves an estuarine light adding to or carbon yield the mechanistic reverse involves picking out and asked it's called the retro Claes said it involves picking out mastery of life member that number I said keeping your head 25 foreign light so that sort of right the same value of chloroform and so I think this is I think the hell form reaction provides us with this
very nice calibration .period for breaking carbon-carbon bonds I saw question there
52 known primarily would once 1 side
you I'm not sure how clean it with I'm pretty action pretty sure you would get a clean Allen the last
substituted side under basic conditions so yeah I'm pretty sure it was the kinetic in all the Member this reactions rate determining in the mall formation arena late formations you form that Connecticut in all or the kinetic Dina light it goes now it's even more acidified so it goes in that position again so I think the answer is yes if we talk that other 1 of the ISA probable methyl methyl example that I was showing you before and tried it under these conditions would
you get all but I still butyric acid would you get some Bromo OIC butyric acid a little bit I don't know for sure we could try it literally in the land of our so that kind of that kind of brings me To what I wanted to say about halogen nation and now I wanted to start talking about some more and I'm chemistry and really this is gonna set the stage for the next chapter but it's also has some very cool
chemistry on its own and this is all there in late alkylation chemistry and presented to us to reactions 1 of them is called the Oceano acidic asters synthesis and 1 of them is called the melodic gestures
synthesis pseudo acidic Astor synthesis is a
synthesis of Mathilde the melodic Acosta said this is a synthesis of carboxyl I guess it's the bold Really Useful reactions they can be done on a bucket scale literally to make kilograms of compound most the LDA chemistry we were talking about sort of fussy you do it in a little flask
with a little bit of lithium making their 10 no-balls 100 Miller malls of compound be a mole if you're lucky but this is bucking chemistry or wanna laid a groundwork of
this and I want to come back to the 2 numbers I told you before so I said If you want people to know numbers in your head for PKA so the numbers you Kincaid are K of 20 and this is sort of a generic key tone so remember I'm writing a generic structure here say 24 generically tone of acetone
the specific example here happens to be 19 but that's not so employed basically figure 20 and remember I said for now the high gets a little less than
20 if you wanna keep another number here had keeps 17 if you can only fit a certain number of numbers in your head just keep 24 all of them are right after about 25 civil use all tell the year demeanor back all right but I want to show you now is what happens if we strive to to have to carbonyl groups and it shouldn't
surprise us that if we have to Carbondale groups the corresponding latest going to be more
stable now the words the key with 2 G tone groups is going to be more acidic the Astor with 2 Western groups flanking a cop flanking a hydrogen is going to be more acidic so this compound here often called acid she'll acetone yeah you wanna get the idea packed Maine you can call it to 4 pentane die alone its nickname its common name is as Sotelo acetone and has a PKK of about if you have 1 feature and 1 Astor price think it's going to be a little less acidic PK is about 11 this 1 this 1 is often referred to as Apple Seed ascertained fish the but dinner if you wanna get all are you packed you can say Ethel 3 so you
turn away but a
nickname a common name is at Sollecito acetate now give you an even more common common name in just a moment but are 2 groups even yet a little bit less acidic now we're talking about speaking about 13 this is called diet Maloney and it kind of makes sense that Diana
full Mallon they should be a little less acidic all of these should be more acidic in the mind of carbonyl compounds if you
wanna give 1 number in your head you don't put 11 if you don't want to attend if you don't want to keep track of all these numbers but the main point is they're way more acidic than a regular carbon yield Compaq part what's the reason for this great Saturday what we already talked about how you can write a Cobb and
I like the residents form for Oneida lake but you've got lots and lots of extra
stabilization by sticking the negative charge on top of oxygen in the European write Amina lifelike resonance structure I suppose of the person here for once but in all my lone pairs of electrons you can write me in the late like resident structural residents structure with the negative charge on oxygen but the cool thing about all 3 of these 1 3 dichotomy of compounds is the extra deal localization
just like the carboxyl like acid spreads that negative charge out over 2 oxygen atoms
and so it's more acidic than an alcohol here we can spread out the negative charge not just on this oxygen and fired on the other oxygen and so it's more acidic then the regular Keatonâ can serve PTA of 9 now what is not the main line means that unlike acetone if I go ahead and trade s until acetone if I 282 for painting died with sodium hydroxide I'm going to have an equilibrium of that's going to lie to the right to give the corresponding at hand but corresponding late sodium will be the counter identified 1 of trying to balance the equation remind us that water balances our equation so we can quantitatively we can story geometrically make
this corresponding inner life because it gets extra resonance stabilization if I
take Ofella lasted Kate and I treated with sodium had not signed again I have an equilibrium that lies to the right for generations of the Milan downright the structure in line with the king Tony and stumbling slightly more contributing resonance structure over the 1 on penalizing the Astor but remember there all 3 residents structures contributing together negative charge of this oxygen negative charge and that oxygen negative charge on carbon plus ethanol and think about it in terms of PKA PKA water 15 . 7 PKA of the acid till acetone 7 that equilibrium wise to the right by by 7 orders of magnitude PK of ethanol's 16 or 17 depending on which number you wanna keep in your head PTA of Apple Latino acetate 11 that equilibrium lies to the right by 5 orders of magnitude no 1 sodium at dockside for the 2nd 1 the first one doesn't matter so much 1 donor money is sodium hydroxide 4 the 2nd 1 what the
sodium hydroxide do with the Nestor you may makes it Levi tax
Astor Carbondale kicks out at the oxide gives the carboxyl like acid the carboxyl against Sadr swaps of proton Wiese pontiff idea there now if you're thinking you'll say Well he keeps saying they had not decided just like hydroxide and many of its reaction so can't add perhaps I attack here we had transistor location on the mid-term sure it can be a tactic in attacked former territory
role intermediate takeout at dockside you're back where you started its this
degenerate equilibrium sure it happens lots of things happen in Carbon Hill chemistry but it doesn't matter it doesn't make any particular consequence this is also why I'm choosing the pair's Sonia Matthau oxide with Apple Latino acetate rather than say sodium metal oxide sodium that side of course unlike hydroxide will give you a carboxyl aghast but now we're going to get a mixture of the matter last year and the best ethyl ester as you transistor fight alright so where all of this is going is to a synthetically useful reaction which I was hinting at the before the escudo acidic gasses synthesis the
output parenthetically of metal key towns but is this is a reaction it's useful for making them
by the bucket 98 did that there's another
name in addition to Ethel was Acedo ascertain that name for this compound in addition to calling it Ethel 3 acts of Europe that Viewtown away in addition to calling it Apple CEO acetate also gets a call as you always see the tester Tres Oracle thing when you go to the lab and you do an extraction and you ask for Easter and it means that I have to leave the when you go to a bar and you asked for a
glass of scotch you say I'm drinking alcohol because you're drinking ethyl alcohol not methyl alcohol
and hear a pseudo acidic Esther means the ethyl ester of a pseudo received acid from historical terms let me introduce the reaction animal talked about the the mechanism because the school is that in addition to being sensible alright so here's a receipt or acidic gasses there will treat it with sodium math oxide in ethanol very easy to make you throw a chunk of sodium into ethanol it it is is it doesn't catch fire and ethanol fortunately if Jordan to water it catches fire you take an alkyl halide and were talking about 1 that Stewart a destined to well below hairlines but not words not but not
charged futile bromide but something better like Apple II died you can find get away with I probable but you can't fill with church feudal Texas
doesn't do less in 2 weeks finally we throw in some areas said and we discrimination and now the top of a metal key towns where we now have the the odd group on at this sounds kind of abstract so I wanna give us a concrete example so let's say we take animal walk through had occurred Our so let's say we take Apple CEO acetate we retreated with sodium at dockside in ethanol it will take an alkyl halide I'll choose probable bromide could use probable wide-eyed bromides to cheaper than I had iodide probable chloride is I think Ogasawara teeters on the border being gas against probable bromide is a liquid I can buy alkyl bromides into displacement reactions and we do in worker with interests Ansted unspecified but as
I keep saying you can't go and buy a bottle of age 3 0 plus there were talking about a varied CL or sulfuric acid in water and the Mathilde will get out of here with a lot of problems I want to help us keep track that's why have given us a concrete example of the Mathilde we get out of
here is to Haxtun known heart what's going on here start 1st priority and I'm going to give us an abbreviated mechanism because we've seen a lot of the step by 1st parts easier happier and I and drawing 1 of the residents structures of the maker lives easier he wanted broad different 1 that's OK to electrons flow from our nuclear file from the Alpha carbon To the Electra filed with kick electrons onto bromine innocent
you displacement but but but
but but but but with the so now invalid collided with a probable group known not going to balance my equations and show the bromide were just getting a flavor of the mechanism OK next step retreat with acid to do this sake we assess it and what is this incessant catalyze Esther hydrolysis prismatic before the approach the Carbondale water attacks you kick out as swaps some protons around
you take out ethanol all
right so at this point we have Quito West said What the heck a good person ethanol here this is the guy that we're going to focus on the data and OSS and Barrett I think you know acids are especially 1 3 die acids or special they can undergo the carboxyl Leyshon and the mechanisms
really cool going to write a different confirmation of the molecule this is
probably the preferred confirmation where the OH group is hydrogen bonded to the target all I'm gonna stand around this Parliament here here's separate good we can move 6 electrons in a ring like so many that occurs upon when I push chair
arrows let's think about it what is this Maine were forming a bond between this oxygen and hydrogen were breaking this bond or forming a bond between this carbon were forming a double bond over here
formed carbon-dioxide arrival plus call this indeed carboxyl Leyshon that's an OHL there if you're having trouble seeing the policies at the carboxyl Asian because we're losing carbon dioxide so that's kind of kind of intuitive but this also fits into this broad classes of
reactions you learned about 51 Beatty the Paris cyclic reaction but the what's the
archetypal Paris cyclic reaction you learned about 51 B deals all the reaction this is just like the deals on reaction 6 electrons moving in ring if you wanna get technical I can call it a retro immune reaction to try that 1 and 1 of your led TAC they'd made out of seen that before but however you want to talk about it Paris a quick reaction the carboxyl Leyshon reaction rectory in reaction something like the deals the reaction we've broken the carbon-carbon bond and gotten carbon dioxide factsheet told undergoes utilization well
Gedo unilateral right taught Talibanization and that gives rise to the 2 methyl Quito because of course you know also warrants
staples right so let's just put all of this together and I'll show you a call synthetic example something a little bit different we're going to have some fun with this is really is useful chemistry it's chemistry by the bucket you can prepare muffled so will take a receipt Esther will treat it with
our proverbial sodium at dockside the and ethanol we're going to a
double alkylation Morgan alkylate once alkaloid again so I'll take Etheline died from their own gonna continue so we've alkylate and wines but in your mind's eye imagine we're now going to treat with some more sodium at dockside not going to ride it out for you picture this in your mind's eye we treat with some more sodium methyl side we extend generate the Malay words the and now just for fun let's
use of methyl iodide CH 3 realized now we carry out any clear worked out and did and the carboxyl late in the
same way we've done up there but we've got a double alkylation we've put on a metal groups and group and so we can use this as a reaction to synthesize 3 2 Fenton so that's cool that's useful you consider the size of a bunch of Nepal's key towns by way of this chemistry or slays the groundwork for the last section that I wanted to talk about the melanogaster synthesis the
carboxyl acids
already showed you die Apple Maloney that was the 1 with the 2 carboxyl exacerbates the 1 3 digested again the old nickname for it is melanogaster because it's the guy at the last year of melodic we already said well Ethel is sort of the default so we take our
Diana told Maloney also available
cheaper like CDA effortless Ito acetate I'll talk more about how all of these formed as we get into the Clayson reaction and chaff to 24 so we take our melodic and now we're going to do the same type of chemistry we're gonna 1st Street was only a matter of fact slide in ethanol Will the industry with an alkyl halide again we're talking about an
alkyl halide that Stewart displacements and Upchurch fuel bromide but a
primary alkyl halide maybe even the secondary helpful here lied and finally will carry out make Rios and he went with assets the product of this reaction is the corresponding carboxyl like gasses
chemistry is very
very similar to make the Malay alkali Hydro lies the Esther groups 2 the corresponding carboxyl like Gaston had to die acid years are dying acid I guess I'll write it once sort normally see you can
see that and all right it once in a more realistic confirmation an internal hydrogen bond just like we we
did in the other cases again we're going to punish or electrons in a ring of white cells we lose carbon-dioxide just as we did before we get all former of the carboxyl said to
retort from arise but at the
end of the or where I want to conclude is coming back to the
idea of seeing backwards director of synthetic analysis we've seen the ICT guests in the forward synthesis and the forward sense and that's fine because you figure it out for the backwards and someone assure you this the backward since we already saw on the
midterm exam how you can look at an immediate and take it apart to the corresponding to the tone and meaning to Antonina mean and we can do the same thing to various types of alcohols and we can do the same thing so let me give you 1 more representation in this connection the ride out a little problem here let's say we think want to prepare proper no
answered by the CIA was ceded by the Milan at not by the monarch
synthesis of a bit of a foreign so so we look at this compound and we look at the chemistry we've seen in the melanogaster synthesis we look at the same chemistry we've seen in the Asiad always seed-investors synthesis and we say are what are we really we're really forming this bond the bond between the alpha and beta carbon but I In essence to reactions and so in our minds eye on when we will look at 3 fennel proper knowing we and we say off OK that's the bond that were going to make my and as Centauri action in the melodic Esther synthesis and so we
see something in a big piece now this is what records and Vedic analysis is all about this is what seeing that acetone immediately and saying all
that's the amenities from acetone and handful Maine that's the big side that you get so we look at this and now we say all you were gonna format bond we're going to use the melodic gestures and sister with a Benthall halide and you just go here chemical shelves and pick your favorite bands along light will go with the bromide it's nice and reacted with job with the chloride bromide to remove bit more reactive so we'll start with our melodic will start with our diet for Moulin I will treat it with sodium at dockside in ethanol CNS is altering the LDA chemistry lt really came about in the late 1960's and to me it was transformative in chemistry because it really meant that orchestrating
reaction no tricks I have a told or I'm going to make any light and an alkaloid private after I'm going to make any light where I wanted going out collated here
we have a track because so Havel because Sony month oxide isn't it basic enough to quantitatively pull off the protons on Apple acetate you have an equilibrium that lies a orders of magnitude 9 orders of magnitude to the left on that reaction but by going ahead and using the 1 3 dichotomy all compound with districts were going in saying that we're going to quantitatively get bedding alight them Morgan alkaloid so starting the fact side in ethanol Spain's bromide take reassess that's like sulfuric acid and water across hydrochloric acid petered out but you you have a professional broken against far-right 1 last example from your textbook and I think it's a good 1 so I want to show it to you when really really think our way through it for beginning students inorganic chemistry rings can really mess with your mind and so often when a beginning students cycle aghast at Talat's very very different in their mind then a regular talent course being able to break out of that and see beyond that's really valuable so here is an example of an innocent prepare cycle can carboxyl gasoline and presumably since we're talking about the melodic synthesis we should be thinking about that when you look at cycle painting carboxyl against it and you say Well wait a sec we got his ring in here what we do with it we that were breaking the alpha-beta Poland Williams alpha-beta bond here an alpha-beta Bond we know
only conforms to what we saw on the OCD Augusta said this is where I use ethyl iodide and methyl iodide that you can do it twice and you can do it twice a
year and if you think about it what that means thinking backed words is it means that we're going to have their but we know we put this in quotes because that's the peace coming from Ito CD Castres synthesis and yeah and so that it becomes the crops recognizing that we have a dying beauty and so now all we have to do is put this into action in the forward manifold we start with diet for Maloney found a nice thing the reactions forgiving you been throws them together I've been writing step 1 step to step 3 you can throw me can't throw the acid together with the base once
base but I can go ahead and throw this worldwide with sodium math oxides in ethanol and in this diminished sodium at
dockside can react the probe made alkylate probe made again alkali so that's step 1 at that point we have this stuff you don't even need to to isolate this site will contain I Esther now we just take this just like this with an arrow at each Rio plot dealt the rehired relies we do the carboxyl late and we get our cycle contain carboxyl
at all in 1 fell swoop and that items Chapter 23 C on Tuesday