Lec. 15. Electrophilic Addition of E+ to C=C (Pt. II) & Lec 16. Formation of Carbon-Carbon Bonds


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Lec. 15. Electrophilic Addition of E+ to C=C (Pt. II) & Lec 16. Formation of Carbon-Carbon Bonds
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Lec. 15. Addition of E+ to C=C (Pt. II) & Lec 16. C-C Bonds
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Vranken, David Van
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UCI Chem 201 Organic Reaction Mechanisms I (Fall 2012) Lec 15 and Lec 16. Organic Reaction Mechanism -- Addition of Electrophilic to C=C (Part 2) & C-C Bonds 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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let's pick up where we left off we were talking about all kinds of electoral pile that indices Seidel bonds for
Romine chlorine Hydro halogen acids we ended up talking about Hydro Mauritian reaction it's a concerted some kind of a 2 plus 2 we call it a cycle addition it's not Paris I click on but it leads directly to additional boring typically to the last substituted position of CC double bond and so it wouldn't talk about the fall of Tiger war Asian are in most cases
and said this is the land of oxidizing that boron carbon bond and so wouldn't talk about the process of migratory displacements
and I'll start off by talking about some hydro bore Asian of a natural product called pining so if you go to the hardware store and you buy turpentine it's used as a solvent this is 1 of the major components that Holland into this stands looking Cairo molecule so imagine using that as a solvent to dissolve Greece but if you expose that too boring or in this case died Moraine remember that associates to give Beach Street you can hide award across this double bonds and the product of that reaction but did you the Boraine at the last substituted position remember that the boron in the hydrogen had seen to each other they are from the same place of the molecule on sold the Boraine is adding away from me try to draw some stereo chemistry here if the is adding to the face away from his
bulky Quaternary center than you would want the warning to be on top and not on the bottom of the voting centers the draw
this is too the on carbon bond on the top face and although the hydrogen atom on the same face the so that's the 1st the addition of H wore they typically don't want want on their you can't expose that to some sort of an aqueous work upper or lower you anything good with that typically you want to get rid of that carbon drawn Bondra use it somehow and 1 of the most difficult procedures is but to toxic data Lee remove on carbon bond and typically the conditions are drawn like this and I'll speak to that in the 2nd and the important point behind these conditions is that they stereo specifically replaced the boron with an oxygen atom if you have borne out you will end up with a hydroxyl
group up you get worn down you'll get a hydroxyl group pointing down and so that's what that's what makes this procedure so well so useful
"quotation mark at such talk about this this process and so oxidizing was born carbon bond had earlier I didn't mean to drop that sodium hydroxide and hydrogen peroxide really the whole point of that combination that you always see drawn on it is that you're trying to make a hydro peroxide on iron so I want to start off with the sort of example of you couldn't made this through Hi deliberation using due to rated reagent add deuterium and born from the same side this but the sterigenics center here he can track what happens to the war on carbon bond on this and if you treat this with Hydra peroxide and iron again that's the whole point of adding sodium hydroxide hydrogen-peroxide you keep guys who under peroxide make it by mixing base with hydrogen peroxide this creates a very nucleophilic peroxide in I'm so as you might imagine that comes in and adds to this and DPU orbital born on that 1 would love something that in their proxy in mind-set that helpful effect as a nuclear power and so in that adds in we now have this Hydro proxy groups taking off of visible boron and now it's warning there's a negative charge and all the bonds to boron and nucleophilic anything attached to this becomes more nucleophilic on and so you can imagine that as this bond here this 1 cotton bond becomes more nucleophilic it's now able to break the the weak part of the molecule that's the week oxygen oxygen bars
it's easy to break oxygen up look at the point right there ready to push out on that hydroxide leaving and that's very facile and very
fast and you can see that we don't change the spirit in which limit drove age is an age at this position going back we don't change the stereo chemistry at the sterigenics center on carbon that stays exactly as they were taking this bond something migrating over and so the product is still retains that stereo chemical information that was there in the beginning and so we now and I'll put this system that has and will this born words about in the same place than it used to be although not exactly Cincinnati of hydroxide guess what's going to happen next with this hydroxide in right boron is right there still wanted electrons it's not going to just sit there it will come back in an attack and so you'll get now the rest of this stuff
doesn't matter we've already set the stereo chemistry 4 you end
up with this other warning and this is an equilibrium process by drug that can come in and get popped back out in communicating about the go in coming apart Bekele out will eventually you're going to pop this 1 out and that's what leads to release this is very fast especially during the Opolis work up these exchanges of warning the exchange of all COX-2 groups on Borneo it's so don't be afraid of popular and Alcock side back out on that's occurring with the hydroxide also agrees with the Alcott's that's the mechanism for release of of your alcohol and eventually it usually is in all kinds of OK we have a very tricky reaction that we that we covered on the end discussion section yesterday so this remind you of that so I'm going to draw out a substrate is ready to fragment the bonds so here's a cycle had some drawing the chair with the totalling Leading Group on there and I'm going to use on another chair with a double bond right here I can draw perfect chair if I have a double bond in a six-member drains sold or some sort of version of it that's I shows a little bit of that distortion that's not a very well-run double bonds and make it look more uniform so by Hydro bore this what is it said and type ring system to six-member brings fused together and you end up seeing Hydro Mauritian from both faces but I'm going to draw the product of hydro Grecian from the bottom face here and that particular product there in this particular example there was a methyl groups speaking here after a Hydro board I now have 2 six-member cheers fused together such transit Dekalim Dekalim means 10 carbons but it's of this to 6 rings
fused together so now I have a hydrogen on the bottom face the history of hydrogen atom here it's still pointing out on relative to the boron and so
what this does is it sets this system what was up a set of NT cleaner bonds but got this good leading group here this possibly right there there's that carbon-oxygen bond an anti-terror planar today carbon-oxygen bond with music and color and said that the glorious pen colors here so here that carbon-oxygen bond the anti-terror Periplaneta to that I had this carbon-carbon bonds and so it's aligned with the antibody moral trying to push that out but it doesn't have enough money to do that so we didn't make this pond in the center of these 2 rings more nucleophilic we cannot push out the tussling Leading Group and the way you do that you had some sort of a nuclear power this case he added sodium hydroxide and so that again and gave of
foreign-made intermediate so here is that boron carbon bonds and now it's a
boring 89 an analogy between the all these bonds Series interfere Klinger bonds so here's the task leading group you think appear printer carbon-carbon bond and now here's this nucleophilic warned carbon bond that's donating into the same bonding orbital weakening the CEC bond it's more nucleophilic now that donated the into Buner model for the tussling in parts of the fragments to give you a ring system that's otherwise hard to make this gives you an army a 10 member brain and it's very hard to make 10 arranged if you're not good at drawing 10 numbered brings you could just all redraw the Dekalim ring system integrates the bond in the middle I'm simply going to out the bond so there was an age pointing down here I'm going to focus on the relationship between the agency and they're still
hinting they were indeed before the Indian the product just make sure we need all the product to
make sure that those at Donington from each other and over here I had an 8 pointing out that still pointing out there was each pointing down at that bridgehead position just make sure you retain that relationship will drop a product that doesn't change mind mean you go through that bonded so that's a good way to make 10 member rings that are otherwise hard to make on the that thorny fragmentation OK without got 1 last type of electric power other than bore on to talk about adding to double bonds and this is really more what can you do with the boron carbon bond will you can make a nucleophilic as well and
His but the people who work for the him for so this is described by a process called up oxymoron duration when the nuclear file water utilities these reactions in water you get a formation of a carbon oxygen binding carbon market about a media covered Oxy Mercury Asian year undergraduate chemistry courses hired examining sense for the class while over 75 per cent the class but used to be that 100 per cent of the class optimal duration and sometimes people do to moderation labs in organic chemistry labs
on obviously that's toxic stuff and they tend not to do that any more people tend not to use IT duration think there's a
radical process for in instantly 100 per cent yield removing that worthless carbon Mercury bond and so what you end up getting in the end if its water if the nuclear follows water is this you get very high Regio selectively in a conical offsets this used to be a very good way for adding on it's hard to get Thursday adding efficiently without elimination reactions aren't so that it can be a very efficient sequence for making oxygen carbon bonds and if you make the problem back to taking nuclear file storage alcohol who files on but again it's the days of events a waning so why should you learn this this is why everything that you will have learned was Mercury just thinking ahead palladium and this is now the mainstay of
organic synthesis so if you know anything about the chemistry of mercury apply their thinking of palladium that I simply substitute PDX to hear a of aka oxidation gets a little
things here at the end but it's the same idea focus on how you think about what's going on here and when you have medals and double bonds on these things started off with some sort of apply complex forming so you typically that would be acetate and Mercury for Nazi Mercury should reaction on this problem that we have is that when you draw this pie complex we can't go all draw my data bond with a -dash we don't always do that we can use that -dash data pondering if we draw solid pipeline we can't use every pushing so what sort of stuck here what we wanted to do we want to show the structure by drawing the data bonded with 1 used aero push you to predict reactivity on scientific just leave out that dated ,comma because I want to 0 pushing to show what's
going on so this is state bonds and causes problems for us but the point is that whenever you have mercury on 1 face or palladium
on 1 face of a price systems nuclear files will tend to want to and from the opposite faces Just Like Heaven united only a minor 1 and if you wanted to in some weird way think about this like this like a metallic cycle propane on I wouldn't be upset and organic Talat tennis would be quick to point out that while the bond distances are consistent with that but that's OK so if you want to think about it like this at least you can now push heroes but there's a lot of you offend a lot of time but about half of the chemistry community by drawing those those signal bonds that so when you come draw the product of this process of having hand when you put these all these pieces on here so when you draw
the product of this process and let me come back here and take off the the 1 of these
groups because this won't really be electrical alike until we lose 1 of those groups typically an acetate so that'll really make now starts to look like a pro made pox on trips to look like an I Donia on it explains why this is differentially substituted you get attack at the tertiary center at the more substituted position rather than the less of the position just like "quotation mark needed a pox sides just like bemoaning lines just like I don't you mind your soul the same idea the attack at the more substituted position and then you lose the proton here that's would eventually and leads back to the system so that you can use the same thinking to think about the reactions of palladium on the lending
anyone other type of example on that's not exactly where palladium is a little bit different from Mercury In
a far more useful sense and I can't think of where we're going to use it in this first-quarter mechanisms class but does it's important to know that the Palladium can induce additions both in a maintenance so I'm showing you this sort of interdiction electrify 1 top nuclear on the bottom "quotation mark so you can imagine palladium coordinate into 1 of the pie pieces of that old friends out when it does you can then get carbon allegations across the face of the ocean where 1 of the nuclear files in this case it's the Eurogroup attached to the plate and gets delivered from the same face and so I'm simply
going I'm not going to draw the pie complex and just going to go on the air pushing like this and so this process of Cobb politician will deliver from the same face on both the
Palladium and the nucleophilic are group typically Errol this is the basis for the Heck reaction on the console agendas Pike complex here that I'm not drawing just like the pie complex Mercury doesn't do that time palladium is great doing that and this is the start of the Heck reaction and many other types of reactions so it's not always on empty because sometimes it seemed delivery typically without Colgrove not with heroin Andrew Adams typically at but not for so that's electrified aisles adding to double bonds and so now we're going to change gears to 1 class of Elektra files that dominates the field organic chemistry and that's carbon-based electrified files so switch off of donations additional asset I drove orations seamer curation so a major change in thinking here maybe not such a major change the let's start thinking about additional cargo can to CCW wants for the pipeline is the nuclear file in your letter follows some kind of cargo can install taking back historically to 1 of the earliest useful examples where a reaction that dates back to 1899 tho 90 minutes so last millenium but it's totally irrelevant and here's my double bonds could be the sort of an Al-Qaeda and taking place of usually in this case and if you take for Malahide and you throw again that's not electrical up for this double bond to attack formaldehyde is incredibly electrical at but it's still not elected Filipino you need some sort of a catalytic gasses To get this to work you need to make that that held by more like a cargo can iron so you can imagine the keystroke made this so scenario you not Sonia mine and there's a resident structural controller that looks just like a cargo can so not going to draw the Carbol Cat residents structure I understand to all this is not solely in 3 Bond-style oxygen but you get the idea that this is very elected like so now instead of having my double bond attack bromine or HBO Maureen I'm going to have my double bond ICC Delmont attack and Oxo in mind I can't resist gotta draw the residents structures just over all in the same page so the resonance structure this looks like this it's really just a cargo cat eyes so that's the other way to think about that at the college museums sometimes called an act so hard so this is this particular resonance form forms I would call environment sometimes called locks among the Oxo copying and copying a means of cargo paradigm where you only have 3 to discarded on this resonance structure it's the same molecule we call this a not-so-new mine on this resonant structure it's the same molecules but again 3 bonds stocks again that call only a carbon with only 6 electrons that across the Union mine in that particular convenient has the hydroxyl group on oxygen which monitors of of this is the basis for the prince reaction but I'll let me draw the final product so we can see what's going on in the
original prints work you get 2 types of products and both of them have new carbon-carbon bonds so the 2 products
that Prince was getting when he studied these reactions and so was the origin of the 2 different products that look kind of different from what happens is you start off by forming after you add formaldehyde you get this tertiary cobble Caroline and there's 2 different dates for this 1 fate for this Is that water can add direct cargo can iron and that's what gives you this it's essentially like an S 1 type reactions where water heads into a couple can you get to hear what the other of product of this results from the nation next to that cover Kevin sort of like reaction so it's not exactly the ones but this this is the same pattern of reactivity that you've seen before cargo paradigms can diverge to give you either edition of nuclear files or different nations and that's why you get 2 different products this reaction in this this Prince reactions sat around for almost 100 years nobody really using it particularly when he a reaction gives you mixtures of stuff that's kind of pathetic ,comma sometime in the 1980's people started to catch on the it doesn't look like a pretty decent wages carbon-carbon bonds and so let's see how we can change up the nuclear file To make that a faster reaction you know formaldehyde of course that's reactive but not every hour heightened not every Kerviel group is is reactive as formaldehyde so let's take a look at it as a series of some of the old friends but they can add Oxo we can add to these kinds of either protonated out hired the hides of Lewis acid into some sort of copying mind that has an oxygen substituent I
thought I would do I want to take a series of double bonds year-ago propane
and trying to draw edge on their got propane which just think about that a nucleophile attacking things and in this particular case it's not anoxic or being in my hand and it's a cargo can I do two-year-old on so the numbers and giving your specific for this electrified July compared the reactivity of this is just a simple CC Delavan like propane but that's not the most reactive double bond while the terminal but if I want to make that reactive what I would do that would put a very long nucleophilic bond like that 1 right next door in Alice silent substantially more reactive in fact that's 10 thousand times more reactive by just think about Raul reactivity kinetics in this case 10 thousand times more reacted by having a nucleophilic signal bond poised on and activating the
FCC don't want if I make the bond little longer I'm sorry my structures look like
migrated and symbols that has just going to confuse for me uses a different can color here is maybe that'll make it less confusing so I wanted to make this more and more nucleophilic by doing something obvious that would make the bond longer I think I have no I don't have enough all I have is the number for the tribunal standing so try methyl stand all compounds tend to be way more toxic tribunals the that is longer bond and so this is now on 10 thousand times more reactive than the silicon into notes tendered the seven-story reactive Howell standings on you order of about 10 million times more reactive than simple things that's the effect of having that that Coddington bond along in bond issue being up that file and if I really want to
suit that up when he put an even better 1 no put a metal
here and I don't have a palladium or at all got is the number for iron but as you can imagine the same sort of effective if you switch to other transition metals it's called Fiat group so sycophantic diner Lyon died carbon and this despite you another factor of 10 over chain which is already on very nucleophilic so even better if you can put some sort of a metal there if you have some sort of an intermediate in your reaction as a carbon palladium recorded rhodium bond you can expect that those involved nuclear fuel and I don't have a number 4 on for this last 1 but my intuition is that it's better than all of these and what's ironic it's with the 2nd row Adam carbon moron upon is long but if you make a boring out of this if at a
nucleophile into bonds that the government have charged that now really suits of the nuclear Felicity
of the signal bonds and if that donating makes it a great nucleophile for adding to things like travel can be users in synthesis but all of the clears 1 way that you can use it in synthesis so what you do is you park a car Caroline precursor right here and here is the precursor it's an acid house but he popped out that my thoughts group you never Carvel can I'm always next to this discarded Angela McGowan draws CCW there but he learned
anything from this series up above here which you learn is that you can really suit this out by making owl silent so
Carbon Silicon bond is super not that double bond making it more reactive and it doesn't make you more equitable carbons it makes it more reactive that card so now you need something that's going to pop album epoxy group and generate cobbled cast iron and a very common Lewis acid try metals I'll translate as a very aggressive silos transfer agent that Silicon wants to get off of that for fleet and onto a regular oxygen and there is nothing new here right here so I'm not going to draw the mechanism for Attack of the lone pairs on silicon and simply going to draw this intermediate might have this trainable silent there which turned that into a good living and so on that does now is
this this now acts as a leading group on To give you an
answer unimagined along presence oxidant pushing out that leading the generated cargo can iron worker being in mind right here 5 Adams away from that nucleophilic physical and 2 different resonance structures you could draw for this 1 resident structure would be to have this C O double bond that talks only minor I'm drawing the cobbled and I'm like resident structure and here we go we attack with the double bonds and the cargo can and that we end up
with is a great couple you couldn't have known this this is why they did this study they were trying to figure out what kind of scary selected
ED that turns out that you get mostly this well this soon I seem to you get this Vegas-style cobbled can with long Carbon Silicon bond that nucleophilic Carbon Silicon bond is stabilizing the Cobble can iron and any nuclear file could be even true could be another oxygen atom could be another oxygen atom in another substrate some nuclear power will come along attacked this and initiate the popping off in 2 steps of the silicon groups in the end product of this and and I don't remember the ice America ratio for this but the major product is this I saw that you get in this but you can't even tell there was ever a silicon there on the registry clever to install that at the very beginning pockets so that's an example of taking the sprint reaction is old reaction from the late 1800's and using it as an effective way to make carbon-carbon bonds but is also did some other variants of this spring's reaction from would caution you in the early days
or people used if you get even the slightest bit of water it's hard to keep the water vapor
you end up getting Tripoli acid as a byproduct floating around and that is on much faster agent for actively investigate up might 1 it's much faster to transfer protons and neutrons facility but they found when they tried to control those using Lewis acids and controls here that it is a triple again as it was doing most of the activation the powerful off leading groups on the the team is strictly was doing very little of that sold it to be very careful to remove this typically by adding died you appearing on to these reactions if you want to make sure that Tripoli gas that is not the thing that's proved mating for that deactivating your Allcock so be careful as In the end of the
year 1 of them that was all I could think of for
1 thing of 4 4 so here I'm going to take money intramolecular example this is now harder and intermolecular edition of an owl stylings but to some sort of anoxic Coveney mind and willing to make that optical media mind by adding a very powerful lock sofa with Lewis acids titaniumtrack tactically right to call for so extremely Oxo filet loves oxygen Titaniums bonds starts or you get Lewis acid activation and so that's our generating are cobble Caroline in effect Paul
drove his Lewis acid complex here I don't feel like you're at the top of the chlorides you don't need to pop off the chloride to make sure that this is
activated its activated just like this so again there's a resonant structure I could draw that look like a cargo cannon but I don't know if I can tell this carbon is now super-duper reactor I have a cell styling of floating around in here is going to attack and may take doubled this this pipeline away from this ,comma I'm going to hand over the Vegas-style Carvel Caroline intermediate Taxable idea behind the silicon it no 1 amateur account my carbons here said don't get mixed up so here's the Carbol can iron there is detrimental Syal group that sort carbon bonds
stabilizing the can iron and all kinds of things in this solution can act as a
nucleophile to top off there's not nobody runs a reaction when 1 molecule if there is any other molecules floating around in solution with with that has long longer on it canal into this and then in the 2nd step pop that off to give the electrons to the carnival so the end result of this after that some sort of a nucleophilic species picks up a silicon Is it will really deliver that Silicon onto this nucleophilic oxygen and so you end up with this as your product floating around in the reaction mixture this is what sitting around before you jump in water to work this summer so you may you have this tendency to I don't like that plus an A-minus it's killing me I have to take off the taking no don't take just leave it there taking loves oxygen on work that you do this
Of the sultan S 4 months of the year when the nuclear-powered yes sorry this is forced steps nucleophile to silicon 2nd step it breaks the bond then no longer adds to that Silicon species that innocence the that end use cyanide showing all of this for elementary steps in order to take us a lot off of here and then really delivered on the back of the end result of this that dumping water on Is this that's Ilija doesn't just stick around on you get tired realize what you really isolated just the freehold Noel couple it's not alike on the it would be a Lilic appeal which was here at home although there's 1 it's Chicago the operation this is a super common version of Helena
carbon-carbon bonds managers strongly and obviously that's not very interesting in today's from world of said is you want to
control the stairs chemistry but if you put Cairo ligands on Titaniums you can get very high levels of Andean Teal selection you can control which face of the cotton yield the Ellis Island had to OK so what are the common Lewis acids with for costs 18 in federal court is very powerful you can at Cairo's on their control the on Stanic Tetra chloride very powerful born try Floyd not quite as powerful but still a good Lewis acid and now more commonly skinny interest on which has bizarre properties it even works in water which as always mystified me skating through fleet is another of common Lewis acids that use for
these types of reactions it's OK so that there is another version of this reaction has nothing to do with Lewis acids if you
wanted to make this process faster 1 way you can make this process battery just tell you to use a Lewis acid you make this electrify all better and of course that leads to a fast reaction that occurs at minus 78 but the other way to make this past year is to make this even more nucleophilic so how do you make analysis island more nuclear fuel but I just taken and sigh laying on hand I throw that With an ally react to the acid I get the the carbon will be more reactors but there's another way to do that and that's too bad take tributyl ammonium fluoride of fluoride and the source and 1 of fluoride which loves silicon attacks that that carbon solution what you end up with a more nucleophilic
Robinson in Bonn and the carbon so that bodies more nucleophilic into donating more enterprise
started camping out the nuclear Felicity that double bond this is now more reactive more nucleophilic ,comma nucleophile so that double bond is more nucleophilic in a canal attack that alcohol now you can even do these reactions with catalytic amounts of fluoride in I'm the only story kinetic amount of fluid Anaheim and you wouldn't have guessed this I don't think you could have guessed that you could have gotten away with catalytic amounts of fluoride in time there's an equilibrium in in the solution a silicon flooring bond is more stable than than an oxygen silicon bond and I'm not going to draw the mechanism of Earth Hour for Silo exchange but there is an
equilibrium here and if you only through on a catalytic amount of fluoride chloride it's released in his equilibrium process can
come back here to we initiate another cycle so the end product of this reaction is this if you use catalytic amounts of fluoride yes it is only the 1st of the 2 countries .period voters the sitting alone at the piano when this since it if you have some sort of a system like this with a fluoride here that the silicon that long nucleophilic bond is donating the price star and the overall system becomes more nucleophilic apply warble becomes more nucleophilic little more nucleophilic how would I drove play can figure out how to draw this 1 game boy so bad that some sort of a nucleophilic orbital novel called this a signal bond for
carbon silicon I don't know if you can see that in the back but I've got a signal bond that's very nucleophilic that's the spot right here and if it's interacting
with some sort of I'm running out of room Europe Isadora words that Yvonne tumbling to get to know orbitals out the demanded to know orbitals out of this system and when get some sort of a new Part I see see things and have to make sure I have that the right number of electrons hand I guess that's only showing that when I showed him his replied I can do this right from the start and end up with another set of orbitals it's going to make the 5 on his on losing theirs for electrons year-to-year to here and I'm only accounted for 2 of electrons in my system yet they this so in other words should I
invite it might take these electrons and move them over then the cotton sorghum 1 has to be moved over here and in the next structures said don't get it if I airline like this then I have to
move the silicon over and that's not what you get don't get that you end up with a big decisions on the basis of that I'll come back and and show you how to do this in discussion section but I have to account for 2 different laurels when you hear that Senomyx assistant for electrons and and I'll deal with that but you end up by donating enterprise .period you make time-honored gleefully is the bottom line OK so so you can see this ideal over and over we can make a double bond more nucleophilic or we can make the electoral filed more electrical so extended to warrant and what I was and once
again we're going to talk about acid helping curses citizen acetaldehyde time I seen tell the electrons on 1 oxygen we are trying to push out the other Alcock group considers this tug of war and so you can take a little more inmates in this particular case I'm taking up arms let me stress reliever From my boyfriend disease here and taking of compound that has 3 Alloa groups on it to make our boring from Algren yard from the boring if I add lithium this kind of a tryout boring thing it now becomes in a complex and
Sinaloa Gallo groups are more nucleophilic and what you could not have guessed sort of course this isn't going to react with this it's not going to have to do reaction the stirred those 2 species
together so if you made this boring was born aid in solution instead with an arsenal nothing would happen to just sit there it's not until you have some sort of Lewis acid and Oxo filet Lewis acid and here's this came as translated and Lewis acid that doesn't want to add to these these CC power Monday another nucleophilic but loves adding oxygen lone pairs so now the silicon he will initiate this process where where this I will translate sigh turns this into a good Leading Group and now the lone pairs can push that out to make a bomb To make my Oxo Kirby Lyon 4 in this particular resolution from drawing the OCS only in the present
structure and I'm not going to draw all the things attached of 1 the
important part is it's of warning the negative charge to not got a fantastic electrified cut fantastic nucleophile and even note intramolecular this reaction is still very fast because minus 70 for this and then you lose the the 2nd mechanistic studies focus so and you'll see people you that very often this version of the again these all variants of the prince reaction basically taking something like a pro made all died and adding it to a CEC doubles and so here is the most sophisticated and clever application of
the friend's reaction and we
had no idea something like this the idea is to let you you know if I have a boring reagent and I want to make that nucleophilic I need to add some sort of a lone parents that and lot I simply use the longer this year on oxygen but only it's there why not use that some might take some sort of a winery agents like this and I mix it together before on other Lewis acid 1 of the longer simply added to the lead exactly do that it's like magic I will when you this now becomes more leptophilic but
look what happens to the born at the same time now that whole system is more nucleophilic
this is more electrical workers more nucleophilic this far this is not nucleophilic at all there's actually an NTP orbital rear-seat something that's not really very electric bill it's something that's not a nucleophilic and you totally change the character you couldn't stop this from happening if you wanted to it's now super-duper accelerated even if the concentration of this is only 1 out of every 10 billion molecules this is so much more reactive than these that you never have to with most coming in in an intramolecular fashion the pre complex before you form see bonds and so the product of this reaction the rest of the way now has a new carbon-carbon bond and which clearly behind these kinds of reactions and makes them Subaru on super important in synthesis is that they always involve chair like transition states and when things that share like transition state you can predict stereo chemical outcome as long as you know the big groups like to occupy Equatorial
positions in cheers public drawl that all disturbed by drawing a chair and I'll fix
some of the positions here so let's start by drawing a chair with an axial and advertorial substituent there and I'll make that my elder high group so far wanna correctly drawn on the chair like transition state here's my album hide that I had in group on the held hike in H R group wants to be Equatorial and there's is no oxygen coordinated to the boron in fact the students on board ones axial ones Equatorial there's the new bond and then making I'm going to somehow make better -dash onto indicated that's that's assortment of long bond that's what that's breaking in will immediately that it's this
fund here that's the new bonds forming as you attack flavor minus here and plus here and now here's my outlaw
boring here's my Alvaro there's 2 substituent out here in this particular case is not going to it's not very interesting and that 2 ages there that's going to become pyramidal in the transition state and in the transition state this is going to become more pyramidal in 1 group is going to be more axle and 1 more equatorial plane even predicted he got 2 different substituent here on issues like stereo chemical outcome in these reactions such fare like transition states and if you take care 205 synthesis Tennessee basically this reaction in a thousand different versions of the bill world but I also have a lot to do what we was we yeah it makes electrical more elected Phillips and his carbon-carbon bond is now donating and applied making the party more nucleophilic so again even
if it looks like this even if it looks like the equilibrium is only 1 per cent to 99 per cent of the small amount of this sittin and there will be doing all the work and any other Hello groups that happened
to found that happened to bang into this externally don't do anything that can bend a million times in overreact but if there is even the tiniest fraction of this it's coordinated will immediately cycle but this would so let's change Ramallah I think you guys could probably extrapolate this anomaly in ways putting long-bond on groups serve for 8 like bonds on how all groups including David Lewis acid on on Allied's at home and the home this going on about it and this may look very similar but it's completely different kind of completely different for this is not an Alice I'm leaning this is of final silence the carbon silicon bond facilities a substituent directly attached to the double and yet you can still get amazingly activity by treating these with Electra files so in this case someone to draw and I O 2 6 sentiments of draw the structure will be know and almost extended from undergraduate organic chemistry this is basically like I too I just got a nucleophilic living room so you can imagine any nuclear power will attack iodine in part out of 1689 sort and species In result here and really care about the fate of the 6 enemy is that this allows you to substitute silicon with Electra files like iodine or bromine and its stereo specifics if you start off in his donkey group insanely bulky group here if you start off with this final sailing you end up with 6 so it's stereo specific and that makes it incredibly useful you can allergens Carvel irons .period about why he did this retention of scarier chemistry that can be because it's the more stable of the 2 isomers at the trans isomers which 1 actually right around time the with a minute I'll I'll come back to this just hold on to this is vinyl filing substitution cannot come back to an explanation for why you serious specificity quite dividend history finishing substitution


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