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Lecture 12. (Pt. II) Addition to Pi Star (π*)

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Lecture 12. (Pt. II) Addition to Pi Star (π*)
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UCI Chem 201 Organic Reaction Mechanisms I (Fall 2012) Lec 12. Organic Reaction Mechanism -- Addition to Pi Star (π*) -- Part 2 Instructor: David Van Vranken, Ph.D. Description: Advanced treatment of basic mechanistic principles of modern organic chemistry. Topics include molecular orbital theory, orbital symmetry control of organic reactions, aromaticity, carbonium ion chemistry, free radical chemistry, the chemistry of carbenes and carbanions, photochemistry, electrophilic substitutions, aromatic chemistry.
Biosynthesis Ionenbindung Kohlenstoff-14 Left-wing politics Bearing (mechanical) Organic semiconductor Wursthülle Columbia Records Methylgruppe Organic chemistry Meeting/Interview Addition reaction Chemical structure Hydroxylapatit Tamoxifen Chemical reactor Naturstoff Phase (waves) Ethylene-vinyl acetate Carbonylverbindungen Chemical reaction Chemistry Falconry Hydrogen Computer animation Soft matter Metabolic pathway Functional group Yield (engineering) Can (band) Auxin Revenue Hope, Arkansas Stereoselectivity
Ionenbindung Lecture/Conference Meeting/Interview Functional group Radiation damage Controller (control theory) Hope, Arkansas Carbon (fiber) Translation <Genetik> Wursthülle Falconry
Lactose Angular mil Mutilation Chemical reaction Wursthülle Columbia Records Falconry Man page Hydrogen Tiermodell Lecture/Conference Functional group Controller (control theory) Chelatbildung Substrat <Chemie> Cobaltoxide Sea level Soap
Lactose Ionenbindung Hydride Organic semiconductor Wursthülle Methylgruppe Lecture/Conference Meeting/Interview Anaerobic digestion Functional group Elimination reaction Lithium Aluminium hydride
Sense District Lone pair Electron Lecture/Conference Meeting/Interview Functional group Controller (control theory) Sea level Lithium Cobaltoxide Wursthülle Falconry
Systemic therapy Setzen <Verfahrenstechnik> Hydride Lecture/Conference Meeting/Interview Functional group Controller (control theory) Cobaltoxide Inclusion (mineral)
Systemic therapy Gesundheitsstörung Lecture/Conference Functional group Controller (control theory) Regulatorgen Cobaltoxide Wursthülle Lightning
Metal Potenz <Homöopathie> Zinc chloride Nitrogen fixation Deposition (phase transition) Atomic number Columbia Records Circulation (fluid dynamics) Water Magnesium Perchlorate Acid Lecture/Conference Meeting/Interview Zinc Controller (control theory) Chelatbildung
Alkalinity Amylin Magnetometer Lecture/Conference Bromide Coordination number Controller (control theory) Growth medium Salt Ethylene-vinyl acetate Chelatbildung Lithium
Waterfall Metal Trauma (medicine) Ethane Disability Diamond Alcohol Gap junction Acid Epoxidharz Solvent Lecture/Conference Meeting/Interview Controller (control theory) Chemical structure Gemstone Chelatbildung Cobaltoxide Lymphangioleiomyomatosis
Vimentin Battery (electricity) Resonance (chemistry) Carbon (fiber) CHARGE syndrome Columbia Records Ether Systemic therapy Acid Lecture/Conference Resin Coordination number Controller (control theory) Chemical structure Chelatbildung Cobaltoxide
Reactivity (chemistry) Acid Chemische Verschiebung Shear strength Lecture/Conference Meeting/Interview Coordination number Resonance (chemistry) Carbonylverbindungen Protonation Aromaticity Chewing gum
Lactose Neprilysin Activity (UML) Aluminium Atomic orbital Chloride Fluoride Systemic therapy Fat Acid Lecture/Conference Meeting/Interview Boron Öl Process (computing)
Potenz <Homöopathie> Ionenbindung Neprilysin Aluminium Chloride Wursthülle Lightning Fluoride Acid Lecture/Conference Meeting/Interview Valence (chemistry) Auxin Gas to liquids Cobaltoxide Graphiteinlagerungsverbindungen
Chemical reactor Potenz <Homöopathie> Acid Lecture/Conference Meeting/Interview Aluminium Common land Binding energy Chloride Organic semiconductor Recreation
Mixture Octane rating Atomic orbital Atomic number CHARGE syndrome Reactivity (chemistry) Systemic therapy Acid Lecture/Conference Meeting/Interview Coordination number Substrat <Chemie> Cobaltoxide
Lone pair Hydrocarboxylierung Lecture/Conference Meeting/Interview Functional group Octane rating Lactitol Resonance (chemistry) Carbonylverbindungen Organ donation Periodate
Concentrate Octane rating Renewable resource Atomic orbital Carbon (fiber) Collision Chemical reaction Organ donation Vitreous enamel Lecture/Conference Meeting/Interview Functional group Tugboat Altbier Chemical structure Lymphangioleiomyomatosis
Reactivity (chemistry) Ionenbindung Alkane Sequence alignment Lecture/Conference Atomic orbital Formaldehyde Acetone Katalase Acetaldehyde Set (abstract data type) Perfume
Ionenbindung Stickstoffatom Octane rating Wax Katalase Alcohol Electronic cigarette Hydroxide Reactivity (chemistry) Lone pair Lecture/Conference Meeting/Interview Functional group Addition reaction Protein Acetone Cobaltoxide Periodate
Metal Lecture/Conference Functional group Octane rating Addition reaction Sunscreen Formaldehyde Hydrogen bond Acetone Acetaldehyde Organ donation Hydroxide
Reactivity (chemistry) Sodium Mixture Selenite Lecture/Conference Meeting/Interview Functional group Iron Carbon (fiber) Substrat <Chemie> Lithium Organ donation
Mixture Electron donor Atomic orbital Carbon (fiber) Carbonylverbindungen Reactivity (chemistry) Lone pair Systemic therapy Tiermodell Lecture/Conference Meeting/Interview Functional group National Rifle Association
Ionenbindung Atomic orbital Economic sector Organic semiconductor Set (abstract data type) Chemical reaction Leak Organ donation Stockfish Methylgruppe Systemic therapy Water Temporary work Lecture/Conference Meeting/Interview Anaerobic digestion Amine Common land Amino acid Chemical structure Horizontaler Gentransfer Periodate Isotopenmarkierung
Setzen <Verfahrenstechnik> Lamb and mutton Vulcanization Vimentin Agar Carbonylverbindungen Chemical reaction Man page Alcohol DNS-Synthese Man page Zeitverschiebung Lecture/Conference Meeting/Interview Amination
Little Ice Age Hydride Diatomics-in-molecules-Methode Meeting/Interview Lecture/Conference Functional group Orlistat Carbon (fiber) Substrat <Chemie> Alcohol
Trihalomethane Residue (chemistry) Meeting/Interview Lecture/Conference Chemical structure Base (chemistry) Chemical reaction
Seltenerdmineralien Mixture Chain (unit) Nucleotide Chemical reaction Electronic cigarette Lone pair Vietnamese people Meeting/Interview Lecture/Conference Functional group Ribosome Protein N-terminus Medroxyprogesterone Amino acid Active site Base (chemistry)
Mixture Stickstoffatom Protonation Columbia Records Lone pair Adversary Meeting/Interview Lecture/Conference Functional group Boiling Protein Amino acid Chemical structure Lymphangioleiomyomatosis
Setzen <Verfahrenstechnik> Lone pair Stickstoffatom Meeting/Interview Walking Amino acid Base (chemistry) Protonation
Polystyrene Setzen <Verfahrenstechnik> Biosynthesis Residue (chemistry) Metabolic pathway Lecture/Conference Meeting/Interview Recreation Hydrophobic effect
Setzen <Verfahrenstechnik> Biosynthesis Ionenbindung Amylin Hydride Rock (geology) DNS-Synthese Chloride Wursthülle Solution Acid Lecture/Conference Meeting/Interview Functional group Elektronentransfer Derivative (chemistry) Peptide synthesis
Phase (waves) Species Plant breeding Angular mil Set (abstract data type) Solution Chemical reaction Electronic cigarette Lecture/Conference Meeting/Interview Functional group Tamoxifen Side chain Histidine
Stickstoffatom Lecture/Conference Meeting/Interview Functional group Steel Growth medium Chemical reaction
Biosynthesis Galactose Carbonylverbindungen Reactivity (chemistry) Ring strain Water Electron Meeting/Interview Lecture/Conference Functional group Mas (Provençal farmhouse) Elektronentransfer Tamoxifen Recreation Base (chemistry)
Setzen <Verfahrenstechnik> Walking DDT Carbon (fiber) Glycosaminoglycan Valine Carbonylverbindungen Gleichgewichtskonstante Chemical reaction Collision Schwefelblüte Water Systemic therapy Molecule Hydrate Lecture/Conference Functional group Chemical structure Thermoforming
Deformation (mechanics) Valine Gleichgewichtskonstante Water Adversary Lecture/Conference Functional group Addition reaction Acetone Can (band) Thermoforming Bottling line Chewing gum
Setzen <Verfahrenstechnik> Ionenbindung Electron donor Carbon (fiber) Gleichgewichtskonstante Schweizerisches Tropeninstitut Methylgruppe Molecule Hydrate Systemic therapy Water Hydrogen Meeting/Interview Functional group Acetone Chemical structure International Nonproprietary Name Acetaldehyde Thermoforming Dipol <1,3->
Stop codon Hydrocarboxylierung Ionenbindung Activity (UML) Formaldehyde Dörren Solution Death Water Hydrate Meeting/Interview Lecture/Conference Functional group Polymer Acetaldehyde
Reactivity (chemistry) Methyl iodide Ethanol Ionenbindung Functional group Fluorine Electron donor Carbon (fiber) Organ donation Methanol
Chain (unit) Gold Methylgruppe Wine tasting descriptors Medicinal chemistry Alpha-1-Rezeptor Water Meeting/Interview Lecture/Conference Functional group Gemstone Chemical structure Ion channel Periodate Process (computing)
Hydrate Ring strain Ionenbindung Epoxidharz Acid Meeting/Interview Lecture/Conference Cell (biology) Carbon (fiber) Columbia Records
Substituent Kohlenstoff-14 Mixture Substitutionsreaktion Carbon (fiber) Wursthülle River source Propionaldehyd Amrinone Lone pair Acid Collecting Meeting/Interview Lecture/Conference Acetone
and they are all going to continue where we left off on Friday we were talking about
addiction to apply starts so additional revenue yields on if you're not totally up with this go back to your soft organic chemistry text in work every mechanism problem in the chapters on Hill addition testers he's shown Valdai damaged on the medal hope you sort of get back into the swing of things from when we left off we're talking about stereo selected additions and the idea that sterigenics centers there next to carbonyl groups of facts which face you prefer to to add to any Connecticut irreversible reaction and this is the basis for modern stereo selective synthesis of apology died natural products so we talked about this filled in on analysis ,comma and I'm just going to make a little point here that this is on his name what's on the last name it's the way has so far but he had his 1st paper he wrote of the Vietnamese traditional ways last is wind on the so-called the falcon on in-house OK so whenever do some sort of additional nuclear file in this case it's an act how little warning will talk more about these you can understand the mechanism later on this stage center here with this poorly rendered methyl group that's hatched on influences which face you had to that ,comma and I showed you this Falcon on analysis for how to predict which faces preferred and what I said is will number 1 and when there is not a polar group there's a carbon atom here this is a very big but it's because it's just a carbon atom don't consider polar bear you want the nuclear file to attack the opposite up from the opposite phase of the big groups so drawn out to renderings to Newman projections for what I would see I stood right here and sort of you down this this carbon-carbon bond that's the Newman projections and all I have to do with imagine as I stand and look down this carbon-carbon bond is imagine what I see as I looked down that path so there's a hydrogen atoms sticking here and if I oriented to that the big group is going this way I'll have a hydrogen years and it could be that of the governor's bacchanal have a methyl groups sticking up in away swing this this big group all the way around that it's on your left hand side then died at the height of the anger going up and the medium-size methyl group on sticking down to those of 2 reactor
confirmations it would fit with the nuclear file adding from either your left hand side of the right hand side can
still remember 1 of the conclusions are 1 of our party or analytical roles for the falcon on analysis is that the nuclear file attacks from Verdi done its trajectories opposite the big groups and the Breeden damage trajectory over here opposite the the group would look like this and we want to to choose the depiction they want to choose the trajectory that minimizes eclipsing interactions and that's this 1 right here H is small His were coming in forming a bond we don't want to be bumping into some big group here 1 of the bumping into this so others write better and worst and of course when you look at this as a paper that was published about a week ago or something I just ran I typed in that you'd like to practice type in "quotation mark Filkin on into the Asian Journal's website and then start working problems in papers after 500 it's came off you have lots of chances to practice to be good at it because I promise you on 1 of our exams I will ask you this I expect to be so good this that in seminar when somebody mentions the word Belkin on you know the predictions ahead of time and you can see it's very hard when you start to twist around the carbon backbone and translate and that's where all the workers OK so that's the falcon analysis paper they claimed the go sold product was the 1 predicted by the Philippine on rules focus so has come back and look at something that is not filled on it is a powerful source of stereo controls so this is what if it's not broken on it is usually this alternative that's it's not on it's giving you by selecting the cases when you get exactly the opposite of Falcon on prediction in almost
all cases because of this because it was the elation was affecting the reaction Ancram was the first one predict that this was possible and his model stalled because of ankle Akram chelation control soap elation control on
gives the opposite result would be that you would predict from the falcon on analysis and give you an example of a substrate is well designed to give high levels of population control and in this particular case there was oxygen Adolf opposition that's the polar group and according to the falcon on analysis this this oxygen animal bias those 2 faces that the nucleophile wants to attack the opposite from the opposite side of the polar group which is opposite the poll group is not hydrogen to pull group is not this group the polar group is this oxygen but if you try to use the falcon on analysis to predict which
face you would edition from if you added lithium aluminum hydride people and on this case is that the nuclear follows
a nucleophilic aluminum hydride on eliminate hydride bond if he tried to predict using the on an analysis we get the incorrect predictions on the legal and draw out the on the products here an organism ratios this group writers called Benthall Oxy methyl some often called bombs Denzel Oxy methyl so right bomb near gentle hydride becomes-and can either coming from the top face and I are 1 of the year for this southern and this is supposed to be in order to down here and here's the other possible product where the height of the highest little group ads in France but the back faced with 1 of and those are the
2 possibilities so in this case on its favorite significantly and this gives you a sense for what levels of stereo of serious like you can
expect to see it again about a 1995 ratio favoring edition from that face and so why is that that's the opposite of what you would predict if you gone to all this trouble to draw these 2 Falcon on Newman projections for happening is that this happens to be a good whenever you have oxygen and the opposition has turned out to be very good for accumulation of control the Lord's lithium wants 8 electrons and so you at him can I'm floating around in there he loves of oxygen lone pairs hoping into that helping it to satisfy the optical and in this particular case would you would expect to any Alcock see group the opposition be good this is even better because that extra oxygen can actually reach around and binds to the lithium through a three-point relations model what that
does is it forces this oxygen not to be 90 degrees the but forces this oxygen to be in the same thing as the army and so that now creates a face and his
ought to group is now on the top place of that reduces the the public relations ring system so the nucleophile comes in attacks from the back face OK so top faces blocked and so the nucleophile come which is the hydride group all back face but the Laotian review to copies but that's the elation control and it's you find this occurring whenever you have also use some of the types of systems to give good results and so generally what you find somewhere the good he leading groups in 99
per cent of all cases it's somewhat limiting 95 per cent of all cases it's something like this we
have a simple out money right out you'll hear themselves would be 1 of the most common because it's easy to remove eventual group that's a common protected or pyramids Occidental so this will be good for regulation control because it allows the some sort of a medal to go those too old to be gripped by those 2 oxygen atoms here's what's not good any kind of and the more hindered the worst this will be so I don't even want join effect of the strike not good was recently a picture that was published on that show that the words this very specific case for a folding conditions are helpless and conditions where you guests I locked the group said it was so extraordinary and unusual that the jacked communication just some special system where somebody finally got good
relations controls are locked we should as a general will assume you are not going to get good relations and control yes I the protection of the deposition you'll get something on emotive edition of this water
some good medals for arms for chelation control and it's it's generally going to correlate with Lewis city city so titaniumtrack recall arrived for any kind of titaniumtrack place is a powerful Oxo Philip Lewis acids and talk a little bit more about this is just a minute or so Titaniums fantastic that being gripped by 2 metal atoms zinc and zinc chloride potentially the review you often see that you circulation Controls Inc through played even better magnesium magnesium perchlorate magnesium
bromide so magnesium Caroline's the lot of partial positive charge probably aren't you can still see chelation control with
lithium salts so when you're using alkalinity oftentimes you'll see not every time within this list with him as the least good on so many others put a pair of parentheses around that but you can sometimes see a population control looking not always on but I would say more than 50 per cent of the time OK so how do you screw up elation control you compete with it so Princeton's of our readiness so you're not going to get any chelation controlling the NSO inferiors Indiana soldiers solvent why would any self-respecting metal and coordinate with this lame systematic and coordinated act no matter what that every medal will coordinate with units of the medium that you're not going to get any population control
51 understand why the long Bresnan oxygen recently to draw the residents structure of that using the Nigerian you'll see why that oxygen is so good at
coordinating medals and undoubtedly better than your substance according to the metal alcoholics solvents seems pretty obvious to me why you would want to use that as a solitary chelation control because you're you're Lewis acids going to coordinated alcohol impairs and the last of quality you 1 more there will also be bad this is diamond epoxy ethane DME we kind of course that got a built-in healing built into the gap between the 2 and what would you vote on yes it would be the prediction as the fall guy OK so mn last summer put to 2 I hate teenager for this because it's so hard to predict sometimes he'll get in the way of good feeling to middle and sometimes you won't harm but typically
if I wanted to dissuade chelation were sorry if I wanted to prefer chelation control ideas that ethyl ether to stay away from this sometimes you get configuration control but the
long pairs are actually pretty good at coordinating the thing itself if you have a choice don't use teacher if who want to unleash control going it was a ranking series for Lewis acidity like any other choice to throw in some sort of Lewis acid and come makes an author remember to bring at least for Use Kleenex which might have more effective relations I think thank you very much some of them all again winning the view of a series of numbers that came from this study by somebody just use a simple enema analysis to gage their capacity for different Lewis acids to coordinate oxygen acts of Lewis acid and what's the goal of having a Lewis acid coordinate on To some sort of an oxygen atom and the thing is ,comma system to make the the oxygen more electoral positive can puts a formal charge on the oxygen and I dropped the list sorry the resonance structure for this I can see why when I drove the Lewis structure outside the residence structure for this I can I think I can see why nuclear files would be more likely to add to this system formal positive cheap here there's another resident structure that puts a formal positive charge with the carbon listen I'm going to draw that resin that
particular resonance structure so you can see why when you coordinator Lewis acid it becomes faster for nuclear files to attack on my here we're here comes right
on so Lewis acids increased reactivity of carbonyl compounds that's just a general principle OK somebody was very clever and you may have learned this spectroscopy class ready but these protons at the beta positioning owns are really shifted downfield in your shifted way over into the aromatic region because there's so much partial positive charge here In any known and it doesn't matter whether you have Lewis acid they're not begin shifting away Florida down the hill and the better the will assess said the more that Proton gets shipped it turns out you can simply look at at the chemical shift of this Proton on and that tells you all about on Lewis acid strength on so somebody
sizable was very clever to do that simple studies on Monday give you
a list of Lewis acids and the results that you get from that will give users thermodynamics of that process and then from From the inner but tell you about How would make the EU known the High star system more reactive that's what I mean by Duma his firehouses :colon pies starry activities the lowest occupied with words orbital and this is my so sick drawl Susan Lewis acids from which these data born try chloride cost born as an empty orbital the scoring on their the electoral negative compare that to aluminum try chloride and of boron try fluoride more ,comma this is much more common than born trade transcribed try Ethel aluminum you could say the same for trend of aluminum and the last Lewis says that numbers standing Skandia cannot stand Stanic Tetra chloride OK so on if you look at the I'm going to tell you about the ample piece of binding here and I'll ask you to note something that's that's different 1 of these is not like the others while I guess maybe to these are not exactly like the others sold most of these are similar and there's 2 kind of outliers here and I can't believe moment because I can't say I can't believe that that's part of but this year I think that's a negative and I wrote in my positive culture for you here's what's unusual about this but they all predict for used to these powerful assassins and now quickly prefer to
be bound to oxygen In a except for 1 born try fluoride so there's an entropy
component it's very similar for all of these but and sell quickly you would predict that most of the born tried what would not be coordinated your oxygen B 3 spends only a fraction of the time Listen . 1 per cent of the time bound to Aqaba deal so if the have leave finally good Lewis acid in a small fraction of time that is bounded better be having a very powerful so you look at the Lunar lowering in these cases and the units completely unimportant here this is the most powerful Lewis acid on this list and I'm arbitrarily this is measured in electron volts who cares is 1 a begin with small in terms of the effect aluminum strike but try chloride it is not as powerful as the 3 it's a longer bond is really what you're doing you're dropping down to a lower row in the periodic table finally get down to be even spends very little time bound to the Carbondale ,comma oxygen when it is bounded as a very
powerful effect and so you know it's somewhere in this range even tho it doesn't bind as tightly as a tray
aluminum overall it is a very powerful Lewis acid effect trade aluminum is down here and finding that standing Texas chloride .period feathers 1 common Lewis acid that I don't have in this list and I don't know the numbers for that my intuition is the tickle for taking injured chloride fits somewhere around in this region and I don't know where it's an extremely good Lewis acid and I don't know why they don't have numbers for their souls on the toward you say least powerful because standard checked required is a very powerful assessor but all the things on its list of the 10 is this the least powerful based on those numbers organizer Louis acid massively increase of reactor to increase the amount of partial positive charge here they lowered the
energy of the little so you had some sort of a pies stars will know that you were looking to donated to with your nucleophile here's my
orbital energy diagram just as a way to look at that so on you know when you coordinator Lewis acid it's not just a charge effect when according to Lewis acid you lower the energy from the mobile making the oxygen out more Elektra negative all the atoms in the supply system every orbital see that oxygen and analysts lowered in energy OK so Lewis acid at such a meeting later reactivity of your substrates ,comma on the rates of your side and at the
this is 1 of the I want to do it among
the draw series of carbonyl groups functional groups and will put some numbers on the rates of edition of typical nuclear files I want to start up by destroying the important resonant structure for you ,comma thinking key unaffected donation by neighboring Adams slows the addition of external nuclear files so here's what I mean give a carbonyl grouping you're interested in some nucleophile heading in if you want mess that up and put another group here with lone pairs in all messed that up kind of slow that down faded here already got along period is right next door is always donating in how can this compete by colliding
with the Cardinal carbon and this always there it doesn't have to collide concentration of Romario's that affected donations so we draw the residents structure for this film
draw you draw resident structures when you believe that there's going to be affected donations and there's another resident structure the remind you why this is so reactive and other residents structure looks like this that reminds you why can't renewals were selected for the common carving OK so there's no problem the enamel depiction of for this any time you can draw up donation of orbitals and unfulfilled rules there's a mental depiction of it it's in the notes but I'm not going to take the time to show them what I want to do is I want to draw out on relative rates of edition so we can see how this group it's not here by the way how groups that are next-door influence the rate of reaction in a
quantity of waste and I'll come back and run an orbital depiction things I'm going to start here with
formaldehyde extreme Greenlee reacted extremely reactive there's no longer is on the hydrogen atom In opined on the Nigerian Adams there aren't even any signal bond sticking up on the hydrogen atoms that can donate over in the car revealed that nothing is about as reactive you can get sets the top of our reactivity list of I compare that to a key tones like acetaldehyde whether got a C H Bomb 3 of them but any point in time 1 maybe depending on the alignments to but not so perfectly but that the CAT bonds they can donate into the unity bonding orbital and they help decrease the reactivity of this Carboneau and if I put to alkyl groups out there and make it something like acetone going all the
CAT bonds through their acetone is less reactive key tones are less reactive than alcohol that is the general principles of the towns of less reactive than held
up its end and finally not finally but major I can crush the reactivity of this by putting something with long periods on there is an oxygen Bloomberg and never really want to slow down the rate of additional nuclear files money but good lone pairs that a nucleophilic next door like nitrogen appears on its that's why your proteins are made out an advance that keeps them from idolizing spontaneously water doesn't add spontaneously to the backbones of proteins because of that deletion soon I'm going to compare all of these functional groups to enamored of a sign that a relative rate arm of 1 and were interested in our rates of edition of hydroxide so
that's a relative rate of 1 turned up the formaldehyde has a relative rate of additional hydroxide 100
billion 100 million times faster for formaldehyde to react with hydroxide deified and I nucleophile files and compared to this formaldehyde adding that 1 extra metal will cost you a factor of 100 in late so acetaldehyde is 100 times lower than for now but that's the effect a wonderful group that's the effect of the H bonds on this donating in the car Kerviel Phyllis Derrick effects that a smaller part of that it's mainly the donations received funds in the car I come down to as of the 2nd ahead of muscle group is pretty similar to the 1st on cost another factor of 100 and down the Astors there's a bigger jump not just factor 100 now there's attended the 3rd soldier acetone key towns are about a thousand times more reactive minister if you
have some complex substrate with 10 million Adams and a key tone and Ernesta you
should be able to react faster with the king usually led beautiful green yard agents or other things faster to Keaton's canisters ,comma manage costs should expect them not to react this way it's very common to protect means a with with Carter banning protecting groups have put a carbon you'll next the alone here that residents donation is very important so simultaneously reduces the Electra was in the company of and also reduces the nuclear Felicity the nite Shimon Peres but I don't have a number 4 on is also very common this Elcock citing irons minutes or something coordinated sodium and lithium bills are less reactive Indiana and I don't have a number of simply say less than 1 on this reactivity that's OK so again and has come back to this but why isn't Esther and reactive what is
this picture telling his residence picture that I belong pair donating into a carbonyl groups like investor money dissect out this Esther here handled all
these these pieces of the puzzle the stirred up by drawing the donor group here if I want to think about what's the effect on the reactivity on this piste system what's the effect of his lone period nearby ,comma John orbital energy diagram to think about the interaction of this lone pair with this piste our systems and to try to think about using models some sort of orbital energy diagram what's the effect so unfilled orbitals are higher energy than Phil laurels here's my pies .period for carbon Hill group say my 2 pieces here's the Kerviel piste or use a nucleophilic I've sort of looked at around so I wanted to think about the interaction of these 2 pieces of a makes to orbitals I get to orbital that I get 1 orbital that's lower in energy and 1 oral its hiring energy and what's the symmetry of these 2 new models that I get out the
panel like but that's what I really Yukon felony label implies something so I get to
know orbitals out when the need to bonding orbital 1 is filled his orders and the little interaction diagrams and this is filled with the bottom water what it tells me right look at all those that idea is when I have a donation like this if I had donation where this With his long period donates this system actually will now have a higher priced all my handle diagram is telling me it is now harder to ads To Ernesta pies stock because of their donations now I don't expect you to diagrams right I just expect you to look at this as the only other along donating and that's lasted around here but if you ever need to open draw diagrams to back up your thinking use of this sector this into a set of orbital interactions each with an associated with this is and who would so for methyl amino puritanism very common catalyst for organic reactions here's the structure of the map president methyl amino group for position of the security men and Wolfgang state leak was studying something called the on the dock in West reaction 30 years ago this has nothing to do with the docking West reactions and was doing those very strange reactions of amino acids you realize
that this type of catalyst has an extraordinary effect maybe I can use it for other reactions of carbonyl groups and so when he shoulders if you take a typical
installation reactions it's not fast enough for you you can simply add 10 more cent but this Amin catalyst not try the Lundy not some not just purity but the man and when you add that to your lady so later on alcohol your performance will transfer reactions on about 10 thousand times faster just that 10 of course to get 21 per cent will 12 2 times 10 4th faster get 10 times more detailed maps you he attended 5th faster so just that small amount of team give phenomenally acceleration and what we now know is that these reactions occur because the Natanz nuclear nucleophilic and I'm not going to show all the euro pushing for this it
italics the carbon Hill grew faster than the other the crummy alcohol substrate
but was you could not have predicted ahead of time is disintermediated seal .period in intermediate is more reactive than the original and hydride and this is also true for radical it's now faster to attack that carbon he'll now that its initial fury any of the others charge leading Group it's right next door that makes gives it more kilometers positive because more of a positive partial positive charge of annual so this is
a mechanism for doing that catalysis on the duties you know this is a very simple and easy way for you to
make your reactions that it it was a general principle analysis so we call this nucleophilic catalysis because the dean of had act as a nucleophile attacked the cardinal 1st we have to do with the fact that so if you look inside the
ribosome the massive structure on their molecularly on the order of 40 million thousands of residues in there and there is a single base residue a single nucleotide in in the ribosome Saunemin million riders omitting 246 right
thousands of avenues in there that adenine 2 4 8 6 2 2 thousand 486 all
the riders on all that size boils down to this the whole wide as long as there 2 position this 1 Bates this 1 nucleotide is 1 base this 1 Adam and that 1 lone pair next to the functional groups Iniesta and nucleophile so
inside the active site of the ribosomes you got in on
a yesterday with an amino acid hanging off the ends of justice minister nothing special about it and then you have your growing protein chain which is just an amenity and the whole ribosome is there to catalyze this a summation reaction were you transfer this Aso group Emmanuel amino acid wants to on the N terminus of a growing protein chain it's only me and
you get a new peptide bond but I'm not going to show you the whole amino acid it doesn't matter the point
is is that this is just part of the whole ribosome all boils down to a single long pair and so was mechanism for this In the Occupational drawn disappear and then you would have here in it's the kind of look similar you know just like 4 D map might think well maybe this longer years donating United a resident structural lining
instantly Felicity that nitrogen maybe that's what the ribosome owners really doing with
that's the whole purpose of this particular adenine the ribosome arm turned up that's not the role and you can never predict that this ahead of time it turned out that 1 single lone pair in the ribosome is just there for this is just there to help the ribosome deep-rooted but this intermediate after that the protein Amin attacks that Esther you generate this would ironic intermediate and as soon as you pull this Proton off there is now a lone pair they can help push out the tyranny leaving and you can't push out that tyranny leading Group until you generate long-term nitrogen it's too slow so there's 2 different very similar things here there's some there's just plain dean at the goes through nucleophilic catalysis right you can imagine this adding to the ASO group generating makes appearing himself but there's also base catalysis and so both
of these are well precedent in the literature hardly tell the difference when you run action whether something is
going to nucleophilic catalysis going through this kind of base catalysis now any 248 6 inside the ribosome does not attack the the cardinal through its just after this nitrogen attacked the generous this intermediate and
then a key step in peptide bond formation is for them this lone pair
to pull this Proton off this territory going to that's just step that the lives of its catalyzing students to read itself when you pull this Proton of Nunavut alone pair consists pushing up leaving not until people political focus with talk about a simple test here distinguish 2 the building In this In the
middle of the range of their John Brown and there was some 1 of the 3 editors for the hour for Science magazine referred this as the most brilliant experiment he'd ever seen in this life and review is being overly incident makes it it's an experiment to distinguish these 2 possible mechanistic pathways and what I want to do is I want to draw a picture for you arm of solid phase synthesis resonated this tiny tiny polystyrene beads the the same types of solid phase residues frying exchange of
peptide synthesis offer some types of DNA synthesis and so I want you to imagine is taking 2 pools of resident to files of
residents here of beads and in 1 pile of being so I've got to and attached to that in a sealed derivative and so in this particular case jewelry back was clever enough to put on on an acid chloride none in hydride that he had a Eichel fennel leaving room so that turned out to be a good Leading Group this natural family and he found some
way to hook this up to the plastic and so it what he wanted to
test wanted a test with is how quickly if I have another pile of the tonight makes the beads altogether but I wonder what would be to help quickly With this Aso Rock transferred to make a new on and what he showed is that if you simply makes the deeds solution there's no transfer Faisal never transferred over here if you physically taken the beads and makes them together and then grind them up if the loan guarantee hammered bond formation
but then what he shows that take simple catalysts like the map on is all which is the
side chain of histidine which is a very similar effects to denounce what he showed is that as soon as he editor middle to solutions that these 2 sets of beads floating around that he met has always come in and pick up this group fly around 280 Sillerman is only an intermediate and transfer to a steel ropes to the other breeds In other words you got 2 different phases here to solid phases but don't react but as soon as you have a soluble our species it's capable of nucleophilic catalysis in there but that leads to a chemical reaction this is so where the end
product of the reaction and this reaction proceeds to win a seat of through and a seal of armed men is
only an intermediate it works because Canada's all attacks in many parts of the leading group and then it it floats around carries a steel group and Jose sealed Mazzoleni intermediates can float around between the beach and income and be attacked by the nitrogen on clothes called the 3 three-phase test and it is proved that it's not just the
basest city the media it's not just the basic city of the solvent that matters you have to
have some group it's capable of wilful catalysis that can literally pick up groups and move them to other people and sold to museums and it's easy to test you actually have to synthesize two-thirds of polemicist words but this is what allows this transfer to occur OK so that's a three-phase the three-phase test can distinguish
nucleophilic calluses from base catalysis and In the the quarter but
the we but for the for the people of good will but for what was the focus on delicate electronic effects in strain effects on the reactivity of carbonyl groups in terms of what I have numbers for is this equilibrium where water is acting as a nucleophile so
that's not a very interesting nucleophile but that's what I have numbers but I'm going to draw Kerviel group in this residence depiction form because I want to
do you can think of carbon healing in mind that the carbonyl group and destroying the trust separated residents structure and the because it reminds us that we're interested in reactions in which a nucleophile attacks the quality of sulfuric water is the nuclear file returns of DDT get numbers for this or water acts as a nuclear 5 minutes and more than 1 step in the mechanism that doesn't matter but were equally interested in the equilibrium constant for formation is called hydrate for formation of this nucleophilic at collider was look at the equilibrium constant as we change the groups on the system and I'm going to compare this to of molecules that
Jordan had an intuition form desktop like the prototype tone the simplest Keaton you can
have so you if we look at the equilibrium constant for additional water it's not making the 0 but it's not 0 there is a will there is some of the hydrated when you just get a bottle of acetone that's where there's hydrate in there it is take acetone right out of the bottle if it's not tried in some way you you might expect to see a little smidgen of OH stretches in your Spectra OK so what happens ,comma as we replace this with groups that are not as
good as a donating so here's what I have numbers for it would happen if
I replaced 1 of the methyl groups of acetone with the Cobble Hill group this isn't a nucleophilic anymore the Ch is your donate into the curriculum make it harder for water to add it up I start the price system here is not as nucleophilic what you see and there's also this sort of dipole effect which destabilizes the STI carbon Hill structure it turns out that water the Heidrick form that is much more preferred now it's like 0 I don't know like a 6 to 10 racial and I don't even know what this is .period 6 equilibrium constants for 6 to 10 ratio of hydrate 6 out of every 16 molecules now exists as the hydrogen this is a better donors siege bonds better donor away and this despite bond and there's this type of thing which is on which is opposing the good acetaldehyde it's
very hard to work with acetaldehyde corsets if you're doing some methodology project and you need to pick acetaldehyde is when the substrate it's gonna stop
because it's hard to get dry acetaldehyde it's very volatile it's hard to get it dry and if you don't get a driving exists is the hydrate in a one-to-one ratio if there's water present if you don't have H E bonds here on this side to donate it turned out the Cardinals very reacted even with water immediate death formaldehyde remember the suitability activity
formaldehyde there is very little formaldehyde in from allied please don't from how
the Dubai apart from outside Sears what you buy when you buy from now guided by this intimate polymer called pair of formaldehyde in which could 1 carbonyl Wilpon 1 from attacked another cardinal group that keep the heck out of you have to crack at FT in order delivery free from outside alternatively you buy solutions in water or
methanol and ethanol exclusion to performance and those exist of the really want to soup up
on the reactivity of the key Tony you could try floral muscle groups on their those are awful awful donors you can imagine the carbon fluorine bonds have no nuclear ballistic there's no nuclear policies ,comma nuclear those are going to attack anything ever so there's very little donation here at the same time
that there's very little donation by this carbon flooring bond floor is also very electoral
negative it's the most elected negative in the periodic table and that increases the partial positive charge due so if you look at the effect here this is all hydrated if there's any water around little sponge up the water and existences this hybrid individual gold looted process stones and someone elected you can guess what the cost of it helps to
lubricate the gastrointestinal tract that's not important .period balloon across only exists like this not and only we try to drop the structure from the crossed on we would profit is actually hydroxy the key towns but they were weren't the medicinal chemistry designers were very clever they put this through is not structure for profits they were very clever to put a floral methyl group on 1 side of the Carbonell and guess what that does to the equilibrium for cycles Asian and you don't have those 2 flying groups on there then you get more of this free open Shane Warne Valencia put that day floor methyl group in their equilibrium very heavily lies on the side of this close chain Foreman has the active species declines to whatever the receptors some ion channel I think is site of
cells ,comma such as somebody using a simple little trick of putting carbon foreign bonds since the requirement OK so sticker looking
at the effects of strain In cycle probing on the beach by cycle program you can buy cycled open on cycle open on that you can buy hydrates cycle broken on probing owner epoxy acid towels and he has a ton of
cycle pro-bono there's nothing exotic about that it massively prefers to exist as the added and it massively does not want to
exist as a key town and this is the effective range restraint if you look at it the intrinsic preference for a hydrated for a carbon atom is for substituent this and wants to be 190 agrees for carbon with Ford and substitutes a dealer of the carbon atom ministry substituent like this that ,comma Nova wants to be 120 degrees and in this case
because it's a cycle propane Rainier doesn't have to be either the fact is that when you got
3 cartons bonded to each other all those Angola 60 degrees and all these angles 60 degrees so it's basically a matter which sucks less you don't get to be 60 it sucks lest be like this police 109 is closer to 60 and 120 cancel cycle program began can't buy that you can only buy acid house which was broken not happy OK so it good start right there and when we come back I'll talk about various ring sizes for key towns cycles and denouncing collection which is acetone and I will talk about on some other tight supply sources