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Lecture 17. Enols, Enamines, and Enolates

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OK so we've been talking about Renault's regional leaders in a meeting
stimulates and when we left off we were talking about you know late but I want to bring you back just sort of Fremont discussion to this 1 example we had when we were talking about how little sigh lanes in our little boring Sinaloa born s showed you how boring additions this as the prototype for many many reactions in organic chemistry and there was this pattern that if you have a carbonyl group that could 1st coordinate twin Holborn compound that complex even if it's only present in tiny tiny amounts in solution can be super reactive because when you coordinate like this you know the more reactive Electra filed at the spot so Coveney mine on the Sox only mine species and a more reactive nucleophile the warning becomes more reactive is born carbon bond becomes more nucleophilic and another possible mechanism this town if if you take 2 0 to yield learn about 3 3 sigma trope agree arrangements we could also formulate this is a 3 3 Signature of agreement that I would accept that if you do that but if you do this you'll of unavailable on oxygen double bond in your product which is a resident structure of what you'd get if you use the arrow pushing nationalism here on OK so before we had talked about this idea that when 2 things coordinated to make a complex the conflicts in the Super reactive Nunavut president small quantity so keep that in mind of its own some of this simple idea of deep-rooted meeting he tones in order to
generating a lights and if you have a substantial entered the alpha position or to substituent you'll create stereo chemistry either he received by the sister
Trans geometry and so you've got to different choices here on freeing knowledge that you can make so with common bases mediations a common but commenters more organic chemistry trample Amin doesn't generate a lot of you late but it generates a mixture of using lights on a new contract those out on something you don't sewage tunnels off toward the you only latex products with sodium hydroxide with potassium TV talk side these are the kind you know it's there really the the the common stock in and lower than in undergraduate organic chemistry courses these tender fable favor this training this harm this Ziyal late so there's an issue here with conical prior logs and dollar miners has the higher priority here and methyl has a higher priority than age so that's the scene laid right
there and that's the modern amply favored you're getting the thermodynamic product
the more stable legal aid is the 1 that forms and you avoid the sort of bumping interaction on what's going on here is that this is an equilibrium going back and forth if you had even the tiniest amount of illegally or story of the tone presence it will help to white catalyze the isomerization of these relates fully show you how that works which is supposedly generate a small amount of this less favorable the INA late like this and you had any key town left over in solution without protons on there that means you have a potential asset in your solution so far if I acknowledge the bases in the event of a carbon and use that to pull off the protons and don't worry about were violating the three-year-old 1 disgruntled will suspend that momentarily In the point is that
you can see how this readily equilibrate your key tone and as the product of this
you get either the EU or the laid out of this she could see how just a little bit of Quito can catalyze this isomerization and this isomerization this transfer Proton's beckoned with as fast if you want to making a late and you want to end up with the thermodynamic going more stable and then it's OK to have a little bit of the tone floating around because it can might catalyze the isomerization so that you end up the thermodynamic from more favorable Zedian OK but usually we don't do that except the least common way to making relates so lithium and ii separable Amad LDA did you Connecticut
elites and you want to avoid a situation that I just painted up above the people what
the war but of this was good drawn a mechanism to enemy start off by warning you we don't use this generic symbol B for a base when you draw the mechanism for Ltd and I'll show you why the mechanism for LDA G pro nation remember all these pictures that I showed you of aggregates aggregates of lithium out there with him compound within the late-season LDA we need put LDA in solution even in teenager that lithium Vermont state electrons in this particular structured only has 2 electrons and that stocks so it's going to be coordinating things teacher molecules lone pairs on there will be popping on popping off eventually this oxygen atom your substrate will coordinate to that lithium and when it does
even if it's only a tiny tiny amount of this species at equilibrium you now have a
situation analogous to that boron of complex that I showed you before I will see you now have a situation where this electoral fathers carbon use more electrical that makes it easier to the probe made here this ch bond because those electrons will donated to the carbon and that makes this because I pick up a minor start and let them make that nitrogen hand along pairs on that nitrogen more nucleophilic and more basic so by complex in this this complex it doesn't matter if it's 99 per cent the tone and only a tiny amount this complex the tiny amount of this complex solutions super reacted and so now I have this six-member during transition state that shows why it's going to be so facile to deprive me a really nice six-member during transition state for deeper nation and the end
product of this will
initially still have all of stuff coordinated riding on an initially immediately release the lithium lithium wants to coordinate to nitrogen so if you wanted to pop off a new mechanism you need a part that offers the 2nd step if you want to show how you generated a naked lithium on usually without anyone there OK so that's the mechanism for deeper nation by LDA important point about this as this goes to a chair transition state so if you take and 205 organics and this issue will according to a great deal of of discussion about the impact of this other sort of sketched out for you now draw some of these bonds in here and I'll feel that stuff in just a moment when you try to make this a bond in front of the chance to to sketch out
in just a moment something to fill in the blanks here to what is what I'm
whenever substituent not equatorial are not axial because this is going to be our carbon younger break here as we deep-rooted mate on here this starts to to lose its double bond character and as we d probe made here as we take this Proton off on will going to start to break this bond and I'm going to draw -dash dares to show were breaking bones so because it's a chair this substituent has an axial on Equatorial preference I'm going to sketch in those axial Equatorial groups and then back-heeled would draw that nitrogen atom that is now so basic so there's a lithium Adam that's joining the the oxygen in the nitrogen and here's apropos groups somebody went to a hard work trying OK let's try lithium die Ethel and let's try the died Beutel and live tried every single combination and it
turns out that isopropyl is just perfect it's very hindering but not to hinder that you can deduct these kinds of transition state and when you this transition
status of the substituent here have a choice that you have a choice between having your mobile axial or equatorial you'd rather have an equatorial it's the H the least candidate species that wants to be axial and the more interesting methyl or whatever is going to be Equatorial and that's why you prefer this particular until you get in this case this would be busy Lake oxygen is opposite to method see get the kinetically less stable in late when you use LDA because the Croat nation goes through this chair transition state we call this the Ireland transition state Robert Ireland's formulated this thing back in the late 1970 s OK so could take a look at all of 1
sort of warning about this easy awful awful confusing nightmare about unity is over the and audio
warning about how spirits can override the so Limoges 1st a picture for these reactions so based on what I'm telling you if you want to isolate the less stable you late you never ever ever want to have access the tone floating around Texas the Tomcat analyzes isomerization between system transient liked what you always do you put in excess of the LDA In your pot you make that 1st using Beutel lithium and isopropyl Amin and then you slowly is that this is what you did I do drogba sorry OK maybe it's
not so easy to use but it's confusing to me some hope yes it is thank you for asking about that sort of
isn't telling you know well the OK so typically would you do you add in Europe here Tetonia drop wise to a solution of excess when you do this there is no point in time at no point is there ever excess heat on floating around but that would be a disaster so really here you don't add LDA gate the Tonya the Quito guilty it just refer to that as inverse editions OK so here's the results that you get if you take ice approval on lithium Dicer properly I you had 3 Penton known to that yeah that drop wise your solution to both as you start off with a slight excess of LDA what you get is not very good selectively if you take a key like this of course you wouldn't really commonly take a Quito
like this for modern synthesis so you'll use slight excess of this isomer here this trans isomer on and that's not really very good
producing great selectively you see great selectivity in case of investors if this is a little bit smaller it's a lot better to form this is the ice and minutes plus slashing minutes about two-to-one 73 favoring the EDI that I've drawn their still lithium strands this is what you get based on that side of the summit Ireland transition state city given oxygen on on the other side oxygen is smaller than Apple to get much better selectivity and so now it's 94 to 6 ratio of favoring this and then finally if you really broke this up he could screw up that Ireland transition state and they could not really all that
great but pitched imagine you pretty Buehler fennel group here but it was you could say that I favor this in late fall we
were about to to 98 on to what's going on with the deal is the issue so what's the higher priority group here FOR oxygen according declining world trade laws oxygen as the higher priorities 101 judge what's opposite to the methyl I look at the higher priority group and that he would only come over here it's not the same anymore it depends on what you have here are what your substituent here on this position so in this case with the oxygen it's 94 per cent of the isomer that I'm showing you there the words it will flip back and forth between what you call him what you call depending on the conical preload priorities of the substituent and finally we come over here there's a lithium species that is drawl that him very well there an hour
maybe would be held more amplify call this why would still call this this is busy isomer here because the higher priority
group is a lithium and a higher priority to appear on his methyl but here the higher pro-democracy the epoxy sold you have to worry about this nomenclature issue what is he and what is the depends on whether you're working with destiny awaits 42 warning lights so the main ideas you prefer these types of geometry due to the violent transition state which you can mess that up this gets to the I think it's been around the block and and talk about that a lot more encamped 205 for the synthesis class and he would win but so you look
at LDA in solutions of Lorillard at the Mamet basis for all the exists mostly as a dimer this is something we talked about before and so typical you make LDA in ths the ether oxygen as a teenager for coordinating this is what LDA looks like insulation and so fortunately there's a small amount of this some of the people of this sort of a monomeric species that's floating around in solution and that's what does all the deep-rooted nation and I don't know what the ratios are but equilibrium massively favors this time don't worry about throwing the dimer I don't wanna see the diner but just remember that it's aggregated mostly in solution like a lot of lifting weights it's the small amount of the stuff that's present the coordinates pure carbon meal and then goes through this Ireland's transition state pretty proved nation so you can mess up all
this Ireland transition state deeper nation business on comeback and draw out you don't always have to draw up a chair In this class so for example
think if I asked you to deep-rooted draw a mechanism for deep-rooted disaster you would end up drawing out something that looks like this who will face don't have to drive in a chair shape in this class I won't ask you questions related to that but it's a small amount of the Mama that then coordinates to the ,comma Neal of or a key town and that's what generates these sort intermediate species that can be predicted that six-member during transitions that they take those protons off and and I just attach it to the wrong positions freaking out here the Rego Park area of the focus so we can mess this
up it's very easy to messes up what I should do before his if you really had something bulky here like instead of oxygen of the table was directly connected you can mess up his Ireland transition state the
six-member in transition state Robert you can also messing up by putting additives in your solution things that coordinate and complex very powerfully to lithium will make it harder and harder for your LDA to coordinate your substrate so for example here's another discrimination and in this case on the using Hexham Apple I was so instead of I suppose so what's the difference here on Monday didn't do a good job of drawing is so the big difference is this is commercially available and you can buy solutions this LDA you make yourself so if you got the money you can go and buy this obviously Chernobyl-style it has occupied more volume than I will work but the bonds are longer so the silicon is farther away from the nitrogen and
overall it's about the same effect as an icicle group so again you can buy but LDA you can buy you have to make that couldn't so putting Esther and with this in
order to permit Esther from 1 of the 4 what's the favor isomer that you get now is not the 1 where the methyl group is on the same side of the box now the muffled works on the same side the lithium and it's those selected is not perfect so that the disease ratio here but the book is typically somewhere in a menacing above 80 but I'll say greater than 90 to less than 10 for this particular example arms and in this case and the secret here to getting this is the at HMP 8 to the solution you'll see this use of the arm of a lot less there's other alternatives that agent PA what is a very powerful coordinator of lithium is the
structure for each MPA if you'd like you can draw a double bond here but I'm going to draw the Senate's fear ionic residents formerly Illinois residents once on just
emphasize the fact that there's a lot of negative charge on the oxygen and because of that it loves to coordinate lithium and it keeps the LDA from coordinating the substrate to disrupted 6 members transition state and ultimately you end up getting the opposite isomers predicted from that comes from the Ireland transitions to focus solely on HMP netted over their fast train that disrupts "quotation mark I think it would be the 1st to be the 1st of all so oftentimes you see people who want to reverse the Helix selectively on the ladder of some powerful coordinator like a champion into the solution someone 1 quite legitimate gripe
against this but this is a carcinogen it's a powerful carcinogens so people tend not to like to use those as consultant here tho is that you never
used to be no I'm usually 1 other way making a late this 1 is very specialized teams from what was mentally not obvious oftentimes I want to draw the simplest the late and that's the 1 driver massive allied and you don't make that the EU later lasted all the by DEA probe meeting acetaldehyde you make the so this is really from acetaldehyde so you don't make it like this you don't make it by the probe mating of
acetaldehyde using LDA it turns out that has it all his soul reactive that agrement it starts doing our goal reactions with itself so if you
want to make LDA you never want to have all the hype at Morrison allied president solution would you do is put Beutel lithium in ths so the converse of this is if you don't want to make it with fast pass all the hiding away don't leave your view lithium sitting around in th every room temperature because they react with each other as the reaction looks something like this let me draw the well when the redrawn this with a bond here but that bond is it is the 2nd if you leave sitting around long enough it will do that concealed metal laid Alpha to the oxygen atoms to generate is methylated teacher since this will happen it's on at room temperature so let me just put in here that's the half-life for
that is 107 minutes at room temperature so
don't put LDA or don't put people th Japan's but United 1 1 only go with you all that the rest of my country later no that's a problem so if you have more Bulacan floating around this can coordinate to that right lithium loves have oxygen is coordinated to it yet it could be coordinated before you're wondering I'm going to drop this in this sequence and now this can fragment this Super Duper nucleophilic this super-duper nucleophilic carbon lithium bond there can donate entered into binding orders for this CEC Vonn who would have thought that but you would never guess that and if you don't electron density into this carbon-carbon bond if you draw with that orbital looks like there's electron density on the
backside that starts to appear in it's that electron density that comes in and donating to Sigma stardom undergo my hero pushing like this ultimately fragment
at the that I just do that right yes the fragmented ethylene and then you get your ass another hiding late as a byproduct and so that you can pop off the lithium and the AA group etc. and that's what gives you the lithium nearly hit so be careful when you put Bulis assuming teacher don't let it sit around on you end up with this problem it is surrounded at room temperature you probably note from procedures at the that the generally doing this on at minus 78 reactions of to listen and she would be in the form of all of them but of all
of these look at the moment on
eponymous new fuel almost never will work with Nicolina lights there's almost always a lithium bound oxygen or something and make transition metals they tend to favor ,comma there but you never work with with making elites is always the account number 1 ponder on this it's gonna Imagen reactions that occur on carbon and you can imagine reactions that occur on oxygen .period about that how would you predict whether you're electrify was going to react with the carbon atom or the oxygen atom does come back to this issue versus all alkylation and I don't have numbers for a cleaning lady have numbers for this stabilized you later where there is an extra copy of the Soviet Quito Lester and and
what I want to do is I want to imagine what will happen if we take various Ethel Elektra files through innocent to
reaction displays the the X 4 were interested in this in this competition between attack and pick a different pattern :colon here between Attack of the oxygen atom versus land is a different color attack of the carbon atoms and held is x influence whether you're attacking noncarbonated attacking on oxygen so see verses 0 alkylation if you want a high degree of sea alkylation then here's what you should do what you should do is you could you should make this is covalent and non ionic as
possible anything you can do to reduce the ionic nature that oxygen will make it less capable as a nucleophile so if you want very
high ratios of carbon alkylation unless off alkylation on oxygen than I would pick the most covalent bond possible here so they drop this where I have for them and what about strong medal here metal plus In other words this metal floating off space like that 2 or covalently bound futures lithium that lithium is bound here actually it's key later between the 2 oxygen ability was tightly bound the oxygen but you want to make this more naked like more more negative Jordan oxygen then moved down the Periodic Table to sodium potassium to cesium which in some cases you'll you'll use and then finally about as naked as you can get that late it's something that so I'm trying to draw a truck
Tetra Ethel ammonium is attacked Troutville ammonium can which can't coordinated alter minus and their cases
that make it all minus so in that case which would get is mostly all alkylation clears the FO group accused Apple ammonium where is if you use the Libya laid albeit mostly see alkylation and there's a new absolute ban the carbon atoms to more covalent you make that oxygen metal bond the more covalent the less negative charge here and we're going to see reactions on part of OK so what's so what can we do to change the electrified this was is going continue so if if I want to attack if I want to favor attack here on this carbon woman clutches review what is it that makes this oxygen so nucleophilic in that case it's the negative charges makes reactions favorable they're
both nucleophilic this oxygen is nucleophilic because there's lots of negative charge this card nucleophilic because the
whole Norway's biggest at this position at this discarded if I look at the home of the Saskatchewan my little NO diagram here and and there's all these orbitals in there but there's this 1 orbital its highest in energy that's the home of and 1 of them ,comma look like what do those 2 electrons where they spend their time it turns out those 2 electrons in the highest occupied local spend most of their time centered about this fall so the carbon reacts because the most recollection spend most of their time there the oxygen reacts because it's got more negative charge a completely different reason so wanted to make some elective all react to faster I wouldn't want to have an electrified that had a lot of negative charge I would want to have an electrified I'll filed just very little negative charge cited very little positive charge so if I did something I can
help the wide-eyed carbon has the same electoral negativity is iodine there's very little partial positive charges this reacts quickly
because the limo was very big on the carbon that long bond mixes that moved the Sigma .period very big on the back end and as I see it as I make my electoral files more and more with Electra negative groups on their bromine is starting to become more lecturer negative and cotton chloride now I stared and now as I make my leading groups being more and more electoral negatives of phosphate so now it's very Elektra native now there's a lot of partial positive charge you on a carbon atom this reacts through further is very reactive for a very different reason and finally at the bottom of my list here I've got the toss late the softening leaving group now there's a great deal of partial positive charge here
at the more partial positive charge here the more I'm going to see reactions that are governed by charge many moral alkylation so I've got a set of numbers here to put things into
perspective so when x is equal to toss a late Bethalto toss late you get a C O ratio of 11 to 18 8th another word to get moral alkylation then you get see affiliation with Ethel costly because mainly driven by charge when is equalized died the leading group there is eagle-eyed but that doesn't mean Keira emits carbon Toshi calculations show that take a mail to so you use ethyl iodide you get Morrissey alkylation than we do not totally reverse it 99 to 1 on but you can flip that balance back-and-forth were focus going
and just summarize what I'm what I'm telling you about which things will react with and I'll try to
summarize it in 2 different ways the start of this matter and synthesis so they want things that are going to react year on oxygen it would be things that have a lot of partial positive charge so for example if you take on high drives they react faster on oxygen you don't get to see a Salesian when make that attack over here more clearly you get all installation if you had a CD can hydride it TMS chloride there's a lot of partial positive 1 that Silicon you get old-style Leyshon you don't get a lot of seaside relations he makes
Ileana leaders they react faster on oxygen if you take things like he lives by that tussling
those react faster on carbon and of course that's what you care about mostly in organic synthesis you care about making carbon-carbon bonds organic synthesis is dominated by reactions like this take alkali Dieter or more or Aldo hides that annulled all reaction those react on carbon faster so those reactions are driven by Homo Loulo interactions not by the fact that there's some amount of negative charges ,comma OK so that's the that's the big idea was just review on what we're saying evaluates all going sketch out this this picture of on the of the whole world so they look at the most
reactive pair of electrons and we're looking down on top of the home while there's a sort of set of orbitals that I have high
symmetry above and below the plane of the board and so in that Homo that appear electron spends most of its time about that carbon it's bigger on the carbon than is on oxygen area and tiny differences in the size of that order on carbon verses oxygen would translate to huge differences in selected our elective file looking for electrons an unwanted overlap with the Madam underwent overlap awareness and because the most rapid electrons spend their time there so so few 1 reactions serve want see alkylation you want electoral files that have small partial positive charges monthly charge electrified files
anyone collective also don't have on anyone electoral that have low lumos because it's a homeowner more-driven interactions in contrast if you want to
react with this 1 thing that have a lot of partial positive charge right reaction on oxygen alkylation is a charge during reaction the 10 you don't want it to be driven by Home Alone interactions you want something with a high level of that I to pick something that would really react quickly announced it would be like this there we go to battle react really quickly on oxygen much faster than on cargo spread of course that's not very useful synthetically but from there would be an example of something that all charged driven OK so sometimes you need tricks around Sereni find the right reagent balance and if you do do want to see a silly and put on the carbon opening later
so remember what I just told you that if you take on a hydride spills will tender form acetate so they react faster on oxygen that's the general principles if you do want Attanasio group here than what you do in this particular case will be exactly that group you can use something called Mendez reagent is a very tricky sort of electrified instead of having an oxygen Leading Group here on this side chloride Leading Group use carbon-based leading group that doesn't put a lot of positive chartered ,comma this is not super Elektra negative like chlorine for
oxygen you can still act as a leading group and so as a
result when you use this kind of on this is called meanders Esther you end up getting a solution on the carbon atoms can adjust a little trick of replacing your typical chloride leading growth but with with a carbon atom that doesn't that's not very electronic at 1 last thing the finish up with this harkens back to this example that I showed you Over here with his war on this is the way although reactions work so if you take some sort of a common he'll compounding you convert that to the ability and later that may not look like a boron an alibi for I'm species you but it's the same idea but I'm not the sort of flip this around this is very similar that our war on species said a got with the
amount can look loves to coordinate oxygen
water and sewage Drolet coordinated species even of its present in tiny tiny amounts this coordinated species now has more reactive electrified and has a more nucleophilic nucleophile now that lithiated Coleen only part becomes more active the important what Montesinos there's a tiny amount of this in solution even if it's mostly dissociated like this even if there is a tiny mountainous all of your CC bond forming reactions go through this mechanism six-member transition and it is also a chair it's that shared like nature of the transition state that allows you to predict seriously activity in al-Douri action we
take synthesis can 205 violent 204 to
people learn a lot more than OK on London finish up the by showing use and switch over to the sort of slide here actually let me and so we just get a handout in class everybody got his hand shows something Obermeier reactivity tables and I wanna talk about this on and they can I compose it is a question component talk about the power of these tables showing you a bunch of all the there's any means any relates and which ones are most reactive and which ones released reactive and it's only going to electrify House cobbled Kanye and things like that and so at some point you're going to get down to wondering Gee is that a good reaction is that a bad reaction so we talked about you know liters he also and these fears
and he also I will leave the 3 common nucleophilic species but suppose I'm excited with this and many in mind we know that in many minds are reactive will then reaction occur
but we learn all this stuff about organic chemistry and we still can't answer the simple question whether this reaction of a good nucleophile until Obama just need a little bit to fix it and we still can answer the simple question of whether it UN nuclear power reactors and electrifying seems kind of pathetic how can it be that nobody's ever measured them and the point is that her admirers measure the stuff he is a hero in the field of organic chemistry so the question is does this happen at home and this doesn't have enough time in in order to form a bond for carbon-carbon bond with war
and so here's how you address this
military commanders In other words to answer that question you need somebody to take the rope until everybody in the group OK you're going measure kinetics for the next 2 years I was able to get anybody to do that heroic work and her admired Capon of
sorry level at this moment here because the course website ,comma because we recognized as among over 2 links here on there's a links page turn on the length the I added a link to her admirers logarithmic reactivity scales and he had to deal with this he wanted to address this simple issues of why can't we
just look this up in some table the fear which reactions of work well in which reactions don't work well and so when you go to that linked to to Myers
reactivity he's got all kinds of tables amended going to click on the first one but just to show you
someone got a full-screen without whatever technology that OK so here's admiring activity scales Richard explain which is looking at is that this whole set of numbers over here on this side is got all the nuclear files just take a look to make sure we can identify the nuclear file folders just a simple double bond attacking things and it's weighing down well it's inverted here the worst collective files top so nuclear files on top and the best nuclear files around the bottom so as we get down to the bottom look there's any hostile that's more nuclear nucleophilic
regular all look here's an owl standing in our little silo analysis Ireland Elisabetta nuclear thousands of locking so as you walk down here nuclear powers
better and better and better and better and better and this is logarithmic these are factors of 10 differences you go from minus 6 2 plus 6 all the way down OK so let's just try to gage what's the difference in a nucleophilic city between just simple terminal within an analysis Aisling how many
times more reactive is and how sigh Lane in just a simple terminal so answer is ,comma
where local travel and then absolutely Felicity parameter of minus 2 . 2 5 forget the 2nd numbers for the moment now it's final silent that's just signed a simple 1 like our old friend apple Siler that 1 . 7 9 so what's the difference between 1 . 7 9 and minus 2 . 2 I can't do that quickly
so well it's not for the war orders of magnitude immediatly these tables are useful Ellis I about 4 orders of magnitude more nucleophilic then simple CC doubled logs "quotation mark matters would
electrify files you looking at and Meyer did that may
stables useful to organic chemist busy he looked at reactions organic chemist he said I'm going to look reactions that forms bonds so we started off by taking had and many started looking at all kinds of nuclear files adding to that sold most of these reactions that he looked at with nuclear policy is looking at the attack to make of UCC bond and it's not that big a stretch to say Well that's the same as if I look at this rate it's the same idea to stabilize Koble can you could redraw that is a sleeveless so his tables are valid for people who care about Ceci bond formation and in general at you so you can you can gage relative reactivity if you walk up and down this stable
relative nuclear Felicity so let's look at the most reactive nuclear files that he measure couldn't measure everything right he didn't measure of utility and that's off the charts but some of the more reactive things he has stabilize the relates he doesn't have any on stabilizing leaks that would be even lower than this than his measurement techniques allowed his got on simple means on here
he's got you means somewhere over on this side so you can gage read reactivity in it's very powerful oftentimes to say Hey this is 10 orders of magnitude more reactive than that 1 equivalent OK conversely he also made measurements for electrified
files he took 18 all silo leaders and Ellis Island and looked at their reactivity with all kinds of Elektra files results come back up to the top of his of his child here for the most reactive species the most reactive species we looked at were simple these are simple programs for just residents stabilize cobbled paradigms a diphenyl on methyl Koble can iron alliance and if you like it or how much does foxy group stabilize that intoned on reactivity you can come down and look if you walk across here it says 2 points 3 so plus 3 overs verses the diphenyl which about 5 . 9 cents about 3 orders of magnitude less reactive when there's enough oxygen place of benzene ring if you can gage the relative
reactivity of Electra files and specifically the kinds electrified how's that form carbon-carbon bonds what's powerful here is it you can't predict the rates of reactions at room temperature he calls extrapolation firing attempted things a faster higher temperature which lower with the room temperature without having gone
into the lad you can predict which reactions are faster or slower by plugging in these numbers you've got a lecture Felicity parameter you got nuclear Felicity parameter Hong appeared that's this 1st numbers the 2nd number here it's sort of like a fudge factor the didn't varies just a little but they're usually close to 1 but they're not always want to look over here there's this fudge factor that's exactly 1 which means it has no influence over here there's other fudge factors for example the Iran has a fudge factor of 1 . 3 1 what that says that during this kind of picky about the electrified says that the sensitivity that nuclear policy depends on which Electrovaya reacted so it's kind of like a sensitivity parameter I usually just forget
that because of you stupid during her to take that into account and you this simple arithmetic there's a very powerful looked on that that you can use associated with states we the idea is the rule of thumb it was the 1st but this is 1 of the 4 of the it was a matter that look like that .period working too well so role Tom Thumb as you can expect reaction at room temperature at reasonable rates like within a day that would be a reasonable but what we mean by react yeah some of these 2 numbers is greater than 5 a very rarely in organic chemistry you have this kind of simple predictive power but this is what you want to get out of this class if you want to be able to predict which reactions are fast which reactions slow
and if you're not sure if you didn't get an intuition by sitting in and listen to the lectures can go to these tables and these kinds of things up if things are
really electrical work for Super nucleophilic were both than those numbers with this number will get higher and higher and higher federal lecture piles will make number higher and better nuclear puzzle makers and higher because of the numbers greater than 5 at this summer's greater than 5 should you can expect things to react temperature OK so let sit for ICC double-blind is nuclear files and we've got a lot of problems on the problems that have practice that
Single electron transfer
Chemische Bindung
Elektron <Legierung>
Fülle <Speise>
Interkristalline Korrosion
Advanced glycosylation end products
Chemische Bindung
Seafloor spreading
Helix <beta->
Organischer Halbleiter
Funktionelle Gruppe
Weibliche Tote
Aktivierung <Physiologie>
Setzen <Verfahrenstechnik>
Gangart <Erzlagerstätte>
Oxoglutarsäure <2->
Spezies <Chemie>
Substrat <Chemie>
Organischer Halbleiter
Chemische Forschung
Organischer Stoff
Chemische Forschung
Konkrement <Innere Medizin>
Chemische Verbindungen
Chemische Struktur
Systemische Therapie <Pharmakologie>
Aktivität <Konzentration>
Einsames Elektronenpaar
Potenz <Homöopathie>
Chemische Struktur
Chemischer Prozess


Formale Metadaten

Titel Lecture 17. Enols, Enamines, and Enolates
Serientitel Chem 201: Organic Reaction Mechanisms I
Teil 24
Anzahl der Teile 26
Autor Vranken, David Van
Lizenz CC-Namensnennung - Weitergabe unter gleichen Bedingungen 3.0 Unported:
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DOI 10.5446/19233
Herausgeber University of California Irvine (UCI)
Erscheinungsjahr 2014
Sprache Englisch

Inhaltliche Metadaten

Fachgebiet Chemie
Abstract UCI Chem 201 Organic Reaction Mechanisms I (Fall 2012) Lec 17. Organic Reaction Mechanism -- Enols, Enamines and Enolates CORRECTION AT 47m09s (as annotated) - "should be (E+N) IS GREATER THAN -5" 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.

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