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Lecture 09. Pt 2. Addition to Sigma Star (σ*)

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OK so well was great job on the exam was very hard to
get that have increased suggested to might be a little bit harder with that anyways I wanna blame Chris Perry because to on the guys too great an article were continuing on under lectures line in addition to sing stock and really there's 2 reactions they were thinking about when we talk about additional Sigma star orbitals of 1 is Proton transfers for you tap a proton and the other is destined to reactions were we attacked carbon and in each case the leading group leaves simultaneously concerted displaced actions and we spent on the 1st part election Night the Moscow Times
transfers will almost done and I want to finish up our discussion of proton
transfers by talking about equilibria whenever you wrote some drawn-out mechanism furnace verification reaction during Indian hydrolysis anything the turned out lots of proton transfers in those reactions I want to encourage you every single time there's a proton transfers to a new mechanism to try to estimate equilibrium constants that reaction and I'm going to give you 1 example there's nothing special about this this reaction it's acid catalyzed removal of a THP protecting group if you were to draw out the mechanism for this reaction really all of business here is occurring at this prior ran and draw out just 1 of the many proton transfer steps in this mechanism on this PY stands for period any and that's the PTS is his period any impaired toluene sultanate on it's really just toluene soul finding
guested on mixed with but purity so that appeared in
Indiana is the real asset in this reaction and so instructor's reaction were appeared Indian is acting as an asset and and somehow reacting with this text from hydropower Ronald this is a THG protecting group on and let's think about what's the 1st step in this process and and how much interesting thing how much interesting ,comma how interesting can we get with this step so if I drop a barrel pushing for this step all end up with a transferable a proton together Lenox Sonia mind its oxygen with 3 bonds and a positive charge on there we can say a lot about this how likely is that is that a good mechanism why did Knight could make this oxygen is that occurring under the conditions of the reaction so what's couldn't try to estimate the equilibrium constant for the staff and every step where there's some kind of a proton
and what power do we have the power that we have key we don't know there
are 2 tables full of rate constants there you just can't find that kind of information out there but what we have at our disposal are lots and lots of tables of PKC it's very easy to do a titration water and so let's use that information to the PKK April appeared in mind and we talked about the PKK friend many of on before where the protein NSP to hybridize nitrogen atom that's about 100 thousand times more acidic than ammonium ion on firm something like trampoline and the PKA produces about 5 it's for any sp to hybridize nitrogen with a proton if we come over here to there's all this probe made up solely in mind that's kind of like a pro 3rd From made out of the PKK for this particular example is pretty close to the PKK for approximating Peter son and to use the from minus this is not
exactly a regular but close enough for our purposes as
long as I know the PKK is of the 2 acid on each side of this equation I can accurately estimate the equilibrium constant reaction I told you the proton transfer reactions are fast probably under the conditions of the reaction no matter what this does this is probably an equilibrium because proton transfer a much faster than the reactions that breaks carbon-oxygen bonds carbon-carbon bonds and things like that so let's assume that this is an equilibrium and our picture for this reaction is that we're generating some amount of this and then sit around slowly does some associations OK so what's the equation going to use your 1st super-secret equation in Jordan another pair of this case step is equal to tend to them and it's gonna look kind of sloppy and confusing here commemorate for product -minus he gave a reactor I'm
pretty bad with men but even I can handle this equation right to let go through under the Mafia
so the equilibrium constant for the for this forward-looking process here is like this case hue is equal to tend to products minus 4 minus the peak for the reactants which is 5 which is a plus 5 which is equal to 10 to the minus 9 I immediately have some deep insight into what's going on in this reaction when you mix period appeared in imperative with some sort of an ether what you can expect is that 1 out of a billion molecules as programming by choosing to use PPT as you set conditions for the ratio of the probe the problem is 1 to 10 nite that you know that's enough so the ratio of these 2 species and again it's ratios the intuitive
to use to when you do reaction mechanisms for every billion molecules only 1 of many appointed times program and
it's this that sitting around waiting to slowly dissociate that if you want this reaction to be faster uses stronger acid you'll have a higher fraction both of these molecules appropriated in Point and yes you need to know some of there some later that you have in but I'll just give you a 2nd of the nite so we're getting there will be delivered OK so what OK what's the caviar there's lots and lots of people cases that have been measured out there because it's so easy to a titration almost all speaking so there are going to be some differences when you when you take into account well this is not exactly water methanol not exactly water and especially in organic
solvents feel free to use your aqueous PKC anyway it's better than nothing will still give you insight and unless I
suppose I can't imagine asking you some question Roanoke instituted in and rather use not with the cage not try to think in these terms I'd rather you thought with these kinds of numerical terms using not speaking depends in this case I'm going from neutral to charge which you can imagine other cases where you go from negatively charged and neutral and that's what has an impact order you want from neutral things in part to charge charge things and that's what effects the focus of the step backward on with proton transfer I said in this lecture we're going to talk about 2 to 2 different types of addition Sigma stock in the indicates a President transfers were talking about additional Sigma stock for some sort of federal Adam proton bonds and so I would draw like this and I could take exactly the same nucleophile exactly the same narrow pushing attack the carbon atoms and and now it's not the same orbital anymore now I give it a different Michael listened as into reaction as opposed to a prudent with pockets of Hardy's different what I mentioned to you before it is fundamentally different to displace to duel displacement reaction on Proton because that's a 1st row out to remember a periodic table H is over here in 1 corner of the Paris table in the 1st round and then over here in the 2nd row we got ,comma so carbon is more massive a methyl group is more massive than a proton by a factor of 15 it's 15 times more massive than vibrates more slowly back and forth in look and I are in confirm that so immediately should suspected that additions to problems are going to be that kind of displacement ,comma is going to
be slower significantly slower but there's a difference here in what's driving these reactions in photon
transfers remember the actual mechanism involves formation was part of a hydrogen bond so even know both of these types of reactions are governed by the fundamental equations that we talked about on day 1 it turned up the time transfers are mainly governed by charge this is mainly a charge into action that's why Proton transfers so there's very little of this field and low on fuel memo business powering this and making it it's the fact that tended to have negative charge protons have a lot of positive charge things is no wire ascend to reaction is going to be fast turns out that's not the charge it's making this it's contributing to the reason why I dropped it can attack you but I could take a neutral there's and those still attack basking in most destined to reactions this is the dominant species that controlling them so they don't pushing looks very similar but different features for Proton transfers resistant to it's what's talked more about its me and
those are the things that will form carbon-carbon bond trading after being interested in essence
but as you can tell from discussion section and maybe there's generally talking with me I he instantly I Katie together after a 1 year soft organic energy it's the 1st reactor New York you learn you learned throughout the entire year you use it throughout the entire year and overuse use it in every single case where you don't we should shouldn't ought to be using that and so I'm going to everything I can to dissuade you from overusing its into action I I don't think we are so they want to start out by looking at the transition state furnace into reaction arms but just in a very generic sense sense here so it if I draw all the 3 things attached to the carbon it's undergoing displacement and trying to draw this edge on very three-dimensional and so you can imagine the displacing something like bromide over there or armed groups or iodide and in that transition state furnace into reaction we have a nucleophile coming in and simultaneously displacing the leading group as this find is getting shorter hours this distance is getting shorter this distance is getting longer now in that transition state if you look at the distribution of charges on that looks something like this the important point is that carbon
is starting to pick up positive charge in the transition state as this carbon is this extra was leading with those electrons even as the nuclear balls coming in you start to build
a positive charge there's a transfer of charge from the art groups to this this partially positive charge cards in the transition and will see the impact of that a 2nd so some of this rate is down again charge but these are groups are doing their job negative charges being transferred from from Balco groups on the periphery of the Hollies Equatorial we call these up-and-down of begins on a on a treadmill by rental structural columns axial again that's the implication of this idealized transition state that electronic money
and this is true of any trade parental structure that could be an organic metallic species the silicon can the phosphors or it can be
carbon in transition state anything that is treatable by criminals electro negative substituent it was but prefer Ecuador what would it say that those summit axial immediately starting to freak out here for perversity axial all categories they preferred the actual course that makes sense of proxy returns something like a nucleophile electoral positive groups I don't have an abbreviation for this all right out electoral positive so
if you want have fastest into reactions that of course you want have lecturer negative leading groups chloride
bromide iodide acetate UK mine your dad electro negative nuclear files hydroxide and if you really want to be fast wanted are groups attached to that center that's being substituted excuse me while I time my shoe you want to have our groups attached to their carbon atom that's being substituted due to be electoral positive in nature but see the impact of that meant something to him so you look at the rates of than 2 substitution on various things what you find is you
increase the number of chlorine is attached to that that carbon is undergoing substitutions if I compare the these orders 1
carbon atom and so what about what I see if I compare the rates of these 2 substitution reactions what you'd find is that the fuel products of stage wins are the few recordings of between you have on the faster it this is faster the 2 coins die ,comma Maine is slowly U.S. into reactions and that's convenient because you are often used as a solvent reduce a message from reactions I wouldn't it's at least lower than Koroma thing and that's not supposed to be here I followed office was greater than what about rates so and this is faster to substitute the chloroform core form is a better
Solomon president you then 12 minutes also a little bit acidic ,comma Proton but in general it's lowered U.S. into reactions and work on it would be very rare Peter somebody into interaction "quotation mark and
carbon Tetra chloride very slow to substitute it all has to do with this preference for you not to have a lecturer substituent attached to the common you might argue all that the steric effect you know what you're talking malicious Derek's 1st take a look at a different examples I'll just take a look at appropriate well Beutel chloride that's where numbers for verses this toxic not here it's hard to argue hysterically but this is more strictly encumbered oxygen has less scary onto the siege to over there and yet this 1 is 5 times slower by the time slower than a comparable into reaction of just plain beautiful quirk that's not spirits This is the effect of the fact that this oxygen and
oxygen has this polar effectively call inductive effect of carbon it's undergoing
substitution is no conjugation going on here the oxygen is not directly attached to the carbon is involved ,comma but it's an important factor To keep mind as a factor of 5 maybe that's not very big but found it still affects OK so let me keep talking about this tribunal by parental structure because this this feature of trade or by criminal structures is not justice and the transition state it's intermediate anything with traditional by criminal structure mystical look at something else that has treatable by criminal structure so let's take a look at some sort of a molecule like ammonia for that of course is not interesting with protons Donovan imagine 3 different alkyl groups and now this is a Kial center that I have 3 different groups on but you'll have a hard time isolating 1 interpreters the other because it's very very fast for a means to inverse and if I draw with the transition state for that inversion looks like it looks stricken or by pyramidal like this and in that transition state where everything is plain errors and flips up like an umbrella in this transition state you're going to have the electrons in this keyword if its plant the ages the planar there must be a leftover people here I'm not going to change the orbital and finally this thing inverts so that the lone pairs now at the bottom so very very fast for means this process and if instead of a Chinalco groups you use those are not the centers are not considered sterigenics because this inversion so fast but what happens if I replaced nitrogen with other Adams and I'll give you the inversion barriers for these as I replaced on the nite of nitrogen with other Adams in the periodic table so what my giving
you I'm giving value inversion barriers and you can
compare this by substituting nitrogen and ammonia for these other types of cancer would have happened if instead of nitrogen I have a copy and I'm just create ourselves on many periodic table here so I have a Kirby an iron with a longer how fast do carbon finance inverse like ammonia if you look at a few I'm giving you some calculated numbers and so it's important is kind of like the exact number here but the sort of on the relative numbers are imports so violent it carbon
minus 13 the culpable in Virginia is actually very fast and it's fast and
temperature and indeed if you try to make hydrocarbon irons swear that the C-minus there you will have a very hard time trying to work with and isolate those before they good luck but nitrogen there so little slower but still faster room-temperature just or just slower than carbon gasses and finally if turnout Cox I would like to meaningful because there's too long peers but least never number for that and its 1 . 7 OK the important point here is not the differences between all of these What's important is as we drove to the road below this In the list third-row atoms watch what happens to the barriers let's suppose the oxygen plus by the way ,comma phosphorus and I don't know why am putting . 7 if you count 35 and 38 who get the big picture is I'm regretting having that OK here's a huge chance going from 2nd row Adams to throughout this inversion type process that we saw ammonia silicon it's Anaheim's they just plain don't convert if you somehow find a way to make a silicon online with 3 substituent on their you should expect that to retain experienced in history even at elevated temperature you'd have to heat that very hard to get a silicon United to invert like this and mystery construed to rest my boss feet you can buy Carol things were the phosphorus atoms the Carol center they don't do the rest this kind of an inversion very made you happy he had to get to you have to hit very hard sulfur plastic and that's not really that relevant it's something you have to worry about converting but you can see that everything in the 3rd row is
now slowed from 4 so as a general principle the carbon financier fast Bloomberg the well
these numbers came from calculations they calculated the energy of the transition state and subtracted the interview take out from inside the eye everything every number administration down but every number ideas Coquelles from it so there are cases where you will have seen that people have made bombs and worked with configuration we stable calculus for all intents and purposes you for the purposes of inversion you can think about the transition state French version of this popular him as being similar to the programmed on your prediction should be if you put a lecture negative constituents on here on this carbon atoms it shouldn't hurt more slowly if you put electronic it's substituent on a carbon atom it should be harder to gain access to that tribunal by parental transitions to that's why whenever you see people work with configuration only
stable and moneymakers configuration least
interesting by having 3 different groups on there always will be some sort of a header Aladdin attached to the cop and intellectual negative that's when you can start to slow down this inversion process and the back into that down there the part that start to slow down this inversion enough to where you can actually work with those kinds of carbonized before they rest the centuries when you have an electronic soul in this particular case on that the transition state energy friend version of carbon lines like this 1 is about 23 K Cal's promote and that's right at the point where if you keep it cool minus 78 and you can work with the configuration the stables oxygen substituted alkyl at the end because of the day OK so those all properties of traditional by prominent transition states but it is and and what was in the 2 of you who OK so it struck down there that 3rd rows silicon phosphorus and let's talk about the substitution so oftentimes you'll see stuff like this were going to see a lot more of this later on in the course of the more Guyana howled all reactions real old-style group
protection of molecules with TBS chloride when you're going to want to substitute that Silicon off of there what whenever you draw
substitution reactions at silicon there never has been to it's never him to it's to achieve the string or by parental transition state tribunal by criminal socks for the 3rd row out so the transition state to get closer to that is just not good it's it's better to have an intermediate and so I draw that the correct mechanism for substitution that silicon the pop off the common you know what I want to do as do this and then stopped drawing don't pop up a leading group were attacking the silicon for a minute it's not great but it's perfectly happy here with these 5 things attached with silicon and maybe that's going to bother you a lot then you won't want to do it you know I'm telling you don't U.S. and tutors in evidence in 1 part that leaving about but out you can 6 bombs to silicon no architect will for silicon that's the 2nd row you can make stable structures silicon at half 6 font and size on and nothing wrong with with these 5 the now have you do this now you can break that sort of an oxygen bars To make the company only so again even I'm telling you this and it sounds like a simple rule you ,comma I'm going to catch you every time you try to listen to its old enough to head we said don't you listen to concerted reactions in Silicon OK so to the important point is it's the intermediate there really is
trivial by parental was not the transition state in the transition state you're getting closer and closer to trickle by planned focus a lot so I
anytime you see some sort of pentavalent facility in the mind of images say something about the language I'm using we pull this back down were you might have heard may refer to this as a silicon 8 that ending 8 on every time you hear me add a pallid date cool Silicon I drill rate that 8 tells you there's a negative charge on that Adams and whenever there is a negative charter that Adams every single bond becomes nucleophilic so I'm usually really particular about this kind of language because it's informing you of something it's telling you something about their activities so listen for that when year me refer to something as a good great Talladega or any digital
boring OK because these
resent because these intermediate and substitution processes that resemble tribunal by parental transition state all those same rules apply I to show you this Silicon 8 This is the preferred geometry so notice this intermediate got past the toxic displacing From the backside in a two-step mechanisms notice how careful I was to draw a treatable by parental intermediate there Silicon substitution when you look at stable silicon molecules of were intermediates in processes the electro negative substituent 1 to be axial and intermediate electoral positive groups like our group rage want to be which were sold in general when he
substituted silicon nucleophile tends to attacked opposite from the side of the Electra negatively selling you substitute with TMS chloride and you got some
chloride Leading Group now Cox a group is going to come in from the opposite side the Electra negative that's the preferred geometry if he tried to come in from the side you're going to have to pay a price hysteria electronic price for them if you somehow I had some reaction where you wanted to come in from the side and not coming from the back side is not impossible the cost you it's not as favorable as coming in from exactly the opposite of this bond future breaking that favorite coming from the back side found so just to put some numbers on that if I compare the energies of this versus this where I have won the floorings Equatorial
now and not both of the on this structure is 8 . 3 K calls from all hiring
energy to have an electro negatively group on the side how many times more stable is when the Electra native groups are axial so we can convert take calls from all the factors of 10 you can I'm not smart enough to provide a million and shall take that floor the million each time more stable what that means is that you draw some some sort of calm reaction where this thing's comes in from the side rather than opposite the leading group it's like a million at times slower as a penalty I'm not courses can reach around that as entropic advantage for the Commission worry if you've got Eurocopter of
packing docile chloride from the side and that's a million times lower than could attack from opposite the focus of its own
,comma translate this into into biology so this is essentially a model for DNA can be el-Kadi groups there so if I had this sort of on this sort of this would be a fast-running Esther I displaced as a hired realize this with Alcock side and many many enzymes fast real transfer :colon race is like gaze is anything interested Union kind aces Foster cases they all involve some sort of oxygen and attacking the posterior investors want to start off by drawing on the resident structure this so that we can decide what's the preferred trajectory
of attack hydroxide can have from 4 different types of directions here In order to displace the boxing group but according to our rules what's the most
electro negative group that's attached and this phosphorus atoms I've got to mouthfuls closes equal a all minus and about neutral oxygen what's the most Elektra negative group attached to no not only because all minus negative it's got plenty of electron density the neutral it's kind of convenient that's all we're going to this place and if you look at the idealized transition state for this the ideal transition state would be to have abroad as a solid arrow will be to have the hydroxyl attacked unity the orthodoxy that's the preferred trajectory of attack it's not to attack opposite the P double-bond odes to attack opposite believing that this goes through an intermediate there we qualify for 18 and then the
2nd step you pop up leading group it's not conservative and
if you wanted you could have drawn out this the P double-blind 0 resident structural way through every single enzymes that has ever been studying kindnesses like ligation costs the Tasers polenta races every single 1 obeys this rule steer electronics no enzyme has ever been found in which the nuclear file does not attack away from candy to the bond that's leading the Bonitz that the group this leading always has some sort of a hydrogen bond to draw to poisonous structure but also some hydrogen bond to further increases the Electra negativity that group so nature understands this simple flies at every single time designed in such a place so so now I'm going to go back to something that I hope will
be and ,comma well known to you very obvious but it's not so
obvious that I can give you a 1980 was set of numbers here for a while and these are approximate relative rates for nucleophilic displacement of al-Khalayleh it'll start off without with lied on a compare that to this which now has a 2nd nature methyl group on there of the 3rd methyl group on there and then finally I'm going to make that draw another primary al-Khalayleh idea we cannot give the the relative rates for SNG reactions so we should be clear we're talking about a century rates this is the fastest 1 of the bunch the primary alkyl alike I hope you already knew the primary out of the lighter faster pressing students substituted alkyl this as 1 extra methyl group that will accrue to the health of position so we refer to this as the opposition militant acts and you refer to that is to create a physician the more things you had opposition the slower it gets to the U.S. to become more slug of qualify him just now so it's 6 times slower when we had that wonderful responded that we compare this to TB ALL now it's on the order of 100 times lower than these other 2 it's very slow to do this into substitution tertiary sectors but finally when we get to this system which is still Primary Rate the 1st one's primary this is primary this has made a branching methyl groups at the base position and unfortunately there is no way that nuclear file can come in an attack from the back side without bumping into 1 of those enough of their is no possibility for it for that to avoid the bumping and so now we're looking at innocent to rate it's about 100 times slower than so that we call this a Neil Pantel Center this is called Newhall pentane annual candlelight a so Neil handled are the slowest destined to reactions based on steering so that kind of substitution pattern where you have they branching 3 baiters situated next to a leading group those are the worst of all possible lesson to reactions don't propose stuff like that don't design syntheses based on those on Fidel's kill and it it's not as
much as this while been there's still an orbital it back here it's you know if I came in from the side here that maybe it was the worst were coming from the back In my line drawings of and the Justice and maybe that's why the good person around here but the other electromagnets bail on any of these it'll be slower we more but you're asking in terms of relative numbers and might have to go back and look at that Cox like factor of 5 slower so imagine what if I put in Alcock group here maybe 5 times lower than
just as the gap with sitting on the way the 5
used this to something that have like a game like this so that it was leaving this year Bloomberg it is not you I it looks to me and afterward I would expect that to still be some still be a problem but would still would be this much slower the nodes there could be ways you could portend away 2 to make a little extra room so I would know the numbers but they sold stock about three-member because this will turn this on it said thank you think you know everything went you know these rules I do for the Gulf I guess stare it's slower
tertiary stocks never substitute tertiary centers cost me know that I hope everybody knows that ,comma what I wanna do that when
a draw some generalizations four-year Watts here's what I want to drop some want due to contrast these 2 species just a simple Parkside were opening with Alcock sides so if you take a sodium Alcock side and you open up entrepot side you go in addition is nothing surprising about this preferred edition to the primary center but if you don't do that kind of reopening under acidic conditions there is no Elcock side roaming around when you got sulfuric acid that's not what makes a reaction that if you do reactions with catalytic assets it's the neutral or called attacking and it's not the apart said that's opening up its the Sunni mind approved need Parkside and in these cases preferred attack happened at the tertiary sector every time and this is a general principle if you have some kind of role in mind that attack at tertiary sectors always slow that's wrong is the exception to the general so it doesn't matter whether whether you're looking at 0 in talks only a minor ones doesn't matter whether that's a H or whatever Mercury Rainier we don't we don't teach artsy Mercury Asian reactions anymore on that we used to hundreds of your your prediction ought to be whether it's Meadowlark Sonia Missouri Daniel that the nucleophile always attacks at them or substitute center the question is the Walker oxidation if you know that reaction it's all the same more substituted centers get attacked work at the fallacy is that if you draw it where these bonds are equal in size and then it's not so obvious what's going on this bonds already partially broken it's already a longer bond in intermediate registered in July that way so if you want to make it easier to understand you could draw these kinds of things like this where you have a tertiary center in years the Supreme broken bond with this leading route is ready to leave and maybe that'll help you understand why it's faster had to experience but this you have to be very careful with the three-member ring only minds as far as I know that's not true for a four-member arranged five-member bring 6 just remember agreements with this history and I think
that is what we would want to so we give you another series of compounds and look at the relative rates for S 2 reactions so here's another Buell chloride in this case it's a Finkelstein's reaction where you exchange qualified for iodide there you usually "quotation mark sodium iodide acetone and he's always listen to 12 the most typical substrates that you zoning going change the structure of this chloride here and look at the rates for this has sent to substitution process and your tendency may be to want to take your N 1 thinking applied to this From this is destined to talking about here so I'm going sign a relative rate 1 will compare these other substrates in terms of how fast I displaces chloride if you look at our local right here spherically it's pretty similar to the Bureau I just didn't have the number for property societal problem Udall will be produced in its 33 times faster so in other words when you have prices this year by how little there is still not only are the vast difference in 1 day also faster into faster for everything substitutes but surprisingly maybe not so obvious is willing to go to this that would definitely be slower forever and was having an electric negative scientists who that we don't want to cat iron next this electron accepted but if you do yes into reactions that the benefit 3 thousand times faster president if you're going to have to duets interactions make sure there's a price system Nextel
35 thousand times faster I wish my research to go 35 thousand times faster than I'm telling you how to do that if you're you're doing less than 2 and a half we were talking I want you to contrast the transition states frisson to Anderson 1 reactions and let's start off by thinking about as anyone who already had a lot of practice with that and so I want you to think about this process where you simply lionize that I know what's happening in the transition
stick this and want to try to draw a transition state and I'm going to break these down in some really fundamental work here so
in my transition state no the to make this almost pyramidal not yet so very late to transition state is exercising it farther and farther away it's not quite plain area that's trying to get plainer and here's this price system next door this double bond so ultra-religious bending backwards a little and I'm going to try to sketch out a models here in the transition state this is starting to look almost like a P were not quite pure appeared late transition state for necessary action on it almost looks like a horrible Caroline and meanwhile the 6 troopers leaving and it's kind of overlapping with its orbital with this with his MDP World as its leading marching so the transition state in terms of if I were to decompose and these orbitals it would look something like this so the bottom line
is that with 1 reaction with better DP there and this is a general property of a person
transition states this kind of not enough electron that's a sad sad carbon atoms that has an empty pews not enough electrons as we get closer and closer to this cobbled that I need to be in the transition state and so maybe you can tell why it might be happier if right next door we have filled Treasury tragedies is correct so double bond lookout great is that we've got this field orbital right next door tell Tony electron density and that's sad sad provoke out type species that's starting to develop that's why as and when it's faster we knew that the context work and want to contrast this situation will buy enough room here at the Aqaba Neil
next door and not and what I
want you to think about ,comma and SN 2 reaction where nuclear power is displacing the leading group pushing it out like this and that's wrote the transition state now the transition sadist total not just closed a player but is exactly planar was pretty close to exactly it depends on which of these is whatever it's close to play OK so let me draw this out in that transition state it's only it's different now I've still got his start of pure Dolce .period explainer of this continent planar there have to be a P or an elected orderly transition state that looks like a pure about this leading group leaving with its pair of
electrons at Fillmore lawful I've got this nuclear power its pair of electrons at the floral who got all these Oracle's the filled
now leading group nucleophile the problem here is too many electrons there's too many electrons in this transition With the nucleophile coming in with all its electrons there are already enough electrons in here to have covalent bond coming in with your extra electrons that's the problem and now we have a very different solutions now having not just the high bond year but according you'll hear is a better accepted now we have a high star orbitals here at a very low in energy and good donating money phase this final phase this so we can see that as we start to build up too much electron density and we start to orbital it gives us somewhere to go with the summer to donate the
actual like the lesson 1 reaction is not enough electrons S N 2 were looking for a donor actually helpless and that's why Hill is better than a simple CC pipeline
Saigon yet sorry labels is priced .period now because the extra electrons as the electrons villas orbital now I can donate into this on the antibody model for C of the getting the summary Monday have to stop there were almost done with this and you think God on this and I will pick up with that when we come back on Monday
Protonierung
Stockfisch
Reaktionsführung
Besprechung/Interview
Elektronentransfer
Funktionelle Gruppe
Orbital
Chemischer Prozess
Computeranimation
Reaktionsführung
Besprechung/Interview
Gangart <Erzlagerstätte>
Toluol
Protonierung
Aceton
Cold Seep
Tetrahydropyran
Hydrolyse
Biskalcitratum
Säure
Elektrostahl
Elektronentransfer
Funktionelle Gruppe
Periodate
Gleichgewichtskonstante
Protonierung
Aktivierung <Physiologie>
Antagonist
Reaktionsführung
Chemische Bindung
Besprechung/Interview
Krankheit
Gangart <Erzlagerstätte>
Barrel <alpha, beta->
Gleichgewichtskonstante
Sauerstoffverbindungen
Gensonde
Potenz <Homöopathie>
Besprechung/Interview
Ammoniumverbindungen
Wasser
Reaktionsgeschwindigkeit
Stickstoff
Protonierung
Atom
Membranproteine
Bukett <Wein>
Titration
Hybridisierung <Chemie>
Mühle
Reaktionsführung
Chemischer Reaktor
Besprechung/Interview
Gangart <Erzlagerstätte>
Elektrolytische Dissoziation
Protonierung
Chemische Bindung
Säure
Krankheit
Elektronentransfer
Vorlesung/Konferenz
Gleichgewichtskonstante
Pelosol
Gensonde
Spezies <Chemie>
Reaktionsführung
Niederschlag <Chemie>
Besprechung/Interview
Krankheit
Molekül
Gleichgewichtskonstante
Bathygraphie
Chemischer Prozess
Ether
Periodate
Kaviar
Methanol
Antagonist
Reaktionsführung
Säure
Besprechung/Interview
Titration
Vorlesung/Konferenz
Molekül
Wasser
Sonnenschutzmittel
Neutralisation <Chemie>
Lösungsmittel
Reaktionsführung
Kohlenstofffaser
Besprechung/Interview
Setzen <Verfahrenstechnik>
Gangart <Erzlagerstätte>
Protonierung
Stockfisch
CHARGE-Assoziation
Bukett <Wein>
Chemische Bindung
Methylgruppe
Elektronentransfer
f-Element
Adamantan
Kohlenstoffatom
Protonierung
Spezies <Chemie>
CHARGE-Assoziation
Reaktionsführung
Besprechung/Interview
Setzen <Verfahrenstechnik>
Elektronentransfer
Wasserstoffbrückenbindung
Biologisches Lebensmittel
Reaktionsführung
Chemischer Reaktor
Kohlenstofffaser
Besprechung/Interview
Magnetometer
Generikum
Essenz <Lebensmittel>
CHARGE-Assoziation
Sense
Iodide
Chemische Bindung
Thermoformen
Übergangszustand
Elektrostahl
Weiche Materie
Funktionelle Gruppe
Bromide
Elektron <Legierung>
Oktanzahl
Kohlenstofffaser
Bukett <Wein>
MO-Theorie
Boyle-Mariotte-Gesetz
CHARGE-Assoziation
Übergangsmetall
Übergangszustand
Elektronentransfer
Vorlesung/Konferenz
Funktionelle Gruppe
Chemischer Prozess
Spezies <Chemie>
Chemische Struktur
Sense
Übergangszustand
Kohlenstofffaser
Elektronegativität
Silicone
Funktionelle Gruppe
Phosphonsäure
Ausgangsgestein
Acetate
Chloride
Iodide
Reaktionsführung
Elektronegativität
Besprechung/Interview
Vorlesung/Konferenz
Magnetometer
Hydroxide
Bromide
Funktionelle Gruppe
Kohlenstoffatom
Substitutionsreaktion
Chlor
Reaktionsführung
Oktanzahl
Thermoformen
Kohlenstofffaser
Chloroform
Kohlenstoffatom
Hydrophobe Wechselwirkung
Chloride
Sterische Hinderung
Reaktionsführung
Säure
Kohlenstofffaser
Besprechung/Interview
Raki
Sauerstoffverbindungen
Konjugate
Sonnenschutzmittel
Elektron <Legierung>
Einsames Elektronenpaar
Kohlenstofffaser
Besprechung/Interview
Ausgangsgestein
Stickstoff
Induktiver Effekt
Protonierung
Ammoniak
Altern
Chemische Struktur
Übergangszustand
f-Element
Molekül
Chemieanlage
Funktionelle Gruppe
Sauerstoffverbindungen
Alkane
Vimentin
Ammoniak
Eisenherstellung
Krebs <Medizin>
Kohlenstofffaser
Setzen <Verfahrenstechnik>
RNS
f-Element
Lactitol
Stickstoff
Phosphor
Krankengeschichte
Kohlenstofffaser
Silicone
Besprechung/Interview
Setzen <Verfahrenstechnik>
Ordnungszahl
Stickstoff
Gasphase
Formänderungsvermögen
Ammoniak
Härteprüfung
Prostaglandinsynthase
Eisenherstellung
Körpertemperatur
Kohlenwasserstoffe
Vorlesung/Konferenz
Substituent
Chemischer Prozess
Sulfur
Übergangsmetall
Übergangszustand
Elektronegativität
Kohlenstofffaser
Besprechung/Interview
Vorlesung/Konferenz
Ausgangsgestein
Arzneimittel
Konkrement <Innere Medizin>
Kohlenstoffatom
Phosphor
Fülle <Speise>
Chemische Eigenschaft
Reaktionsführung
Übergangszustand
Kohlenstofffaser
Silicone
Elektronegativität
Besprechung/Interview
Calciumhydroxid
Funktionelle Gruppe
Chemischer Prozess
Sauerstoffverbindungen
Substitutionsreaktion
Chloride
Chemische Struktur
Reaktionsführung
Übergangszustand
Silicone
Besprechung/Interview
Vorlesung/Konferenz
Molekül
Funktionelle Gruppe
Ausgangsgestein
Sauerstoffverbindungen
Aktivität <Konzentration>
Oktanzahl
Chemische Bindung
Übergangszustand
Silicone
Elektronegativität
Besprechung/Interview
Vorlesung/Konferenz
LSD
Valenz <Chemie>
Übergangszustand
Silicone
Elektronegativität
Besprechung/Interview
Molekül
Funktionelle Gruppe
Ausgangsgestein
Substituent
Chemischer Prozess
Chloride
Elektron <Legierung>
Reaktionsführung
Chemische Bindung
Elektronegativität
Silicone
Besprechung/Interview
Funktionelle Gruppe
Sonnenschutzmittel
Chemische Struktur
Genort
Reaktionsführung
Besprechung/Interview
Antigen
Funktionelle Gruppe
Chloride
Chemische Struktur
Tiermodell
DNS-Doppelhelix
Gezeitenstrom
Elektronentransfer
Vorlesung/Konferenz
Funktionelle Gruppe
Enzym
Sauerstoffverbindungen
Phosphor
Neutralisation <Chemie>
Besprechung/Interview
Setzen <Verfahrenstechnik>
Hydroxide
Ordnungszahl
Boyle-Mariotte-Gesetz
Doppelbindung
Hydroxylierung
Übergangszustand
Elektronegativität
Funktionelle Gruppe
Mündung
Sauerstoffverbindungen
Blindversuch
Chemische Struktur
Bonbon
Elektron <Legierung>
Chemische Bindung
Elektronegativität
Besprechung/Interview
Gezeitenstrom
Vorlesung/Konferenz
Gangart <Erzlagerstätte>
Funktionelle Gruppe
Wasserstoffbrückenbindung
Enzym
Auftauen
Fülle <Speise>
Reaktionsführung
Oktanzahl
Pentane
Besprechung/Interview
Base
Primärer Sektor
Nucleophile Substitution
Photosynthese
Gangart <Erzlagerstätte>
Sekundärstruktur
Methylgruppe
Vorlesung/Konferenz
Funktionelle Gruppe
Systemische Therapie <Pharmakologie>
Alkane
Sonnenschutzmittel
Lava
Besprechung/Interview
Funktionelle Gruppe
Besprechung/Interview
Bucht
Gap junction
Krankengeschichte
Fettsäuremethylester
Aktivierung <Physiologie>
Schweflige Säure
Reaktionsführung
Quecksilberhalogenide
Oxidschicht
MO-Theorie
Natrium
Primärer Sektor
Stockfisch
Spezies <Chemie>
Chemische Bindung
Sekundärstruktur
Krankheit
Chloride
Elektron <Legierung>
Reaktionsführung
Oktanzahl
Natriumiodid
Besprechung/Interview
Chemische Verbindungen
Substitutionsreaktion
Aceton
Katalase
Chemische Struktur
Chemische Eigenschaft
Eisenherstellung
Iodide
Systemische Therapie <Pharmakologie>
Chemischer Prozess
Substrat <Chemie>
Reaktionsführung
Übergangsmetall
Vorlesung/Konferenz
Chemischer Prozess
Tiermodell
Übergangszustand
Querprofil
Besprechung/Interview
Vorlesung/Konferenz
Orbital
Systemische Therapie <Pharmakologie>
Doppelbindung
Spezies <Chemie>
Elektron <Legierung>
Chemische Eigenschaft
Reaktionsführung
Übergangszustand
Besprechung/Interview
Setzen <Verfahrenstechnik>
Vorlesung/Konferenz
Orbital
Kohlenstoffatom
Doppelbindung
Reaktionsführung
Übergangsmetall
Übergangszustand
Funktionelle Gruppe
Phasengleichgewicht
Elektron <Legierung>
Übergangsmetall
Chemische Bindung
Atombindung
Vorlesung/Konferenz
Funktionelle Gruppe
Orbital
Lösung
Mil
Elektronendonator
Tiermodell
Elektron <Legierung>
Reaktionsführung
Antikörper
Besprechung/Interview
Isotopenmarkierung

Metadaten

Formale Metadaten

Titel Lecture 09. Pt 2. Addition to Sigma Star (σ*)
Serientitel Chem 201: Organic Reaction Mechanisms I
Teil 12
Anzahl der Teile 26
Autor Vranken, David Van
Lizenz CC-Namensnennung - Weitergabe unter gleichen Bedingungen 3.0 Unported:
Sie dürfen das Werk bzw. den Inhalt zu jedem legalen und nicht-kommerziellen Zweck nutzen, verändern und in unveränderter oder veränderter Form vervielfältigen, verbreiten und öffentlich zugänglich machen, sofern Sie den Namen des Autors/Rechteinhabers in der von ihm festgelegten Weise nennen und das Werk bzw. diesen Inhalt auch in veränderter Form nur unter den Bedingungen dieser Lizenz weitergeben.
DOI 10.5446/19227
Herausgeber University of California Irvine (UCI)
Erscheinungsjahr 2012
Sprache Englisch

Inhaltliche Metadaten

Fachgebiet Chemie
Abstract UCI Chem 201 Organic Reaction Mechanisms I (Fall 2012) Lec 09. Organic Reaction Mechanism -- Addition to Sigma Star (σ*) 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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