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Lecture 19. Organometallic Reactions in Organic Synthesis.


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you go on and on and on as we have said today this this
likely there at the end of a very long journey and we've learned so much and I wanted to start by by thanking you for for coming along with with
very timely so today I
want talk about her down a metallic reactions in organic synthesis and know we get to the end of the course we've gone through this wonderful carbon yield chemistry which is sort of the core of synthetic organic chemistry it's logical we've learned these beautiful ways of looking at molecules and recognizing various functionality recognizing beta hydroxy Harvey Nielsen alpha-beta unsaturated carbon meals and seeing the beauty of putting molecules together and we've seen how these types of synthetic reactions like the Robinson undulations can be used to build up the types of structures veterans steroids and all sorts of medicines we've gotten a little bit of a taste of some of the chemistry of Indians and some of the the chemistry that can give rise to to alkaloids and bioactive nitrogen containing compounds and now I want come back to synthesis so we spend a little time talking about sort of natural biomolecules sugars which brought us in beautiful a beautiful refrain on Syria chemistry and molecular conformation polypeptides which showed it's just that he just a taste of not only the structures of biologically important peptides and proteins but also just a taste of how chemists can build up molecules even as big as HIV-1 proteges containing 99 amino acids and 1 of my laments and teaching staff organic chemistry when I started teaching staff more class 20 years ago was there's all this beautiful contemporary chemistry that's going on that really is excluded from the curricula and your textbook does a wonderful job of bringing back 1 facet of this contemporary chemistry that is to use Vedeno metallic reagents and reactions in synthesis realize that the field of organic chemistry is a dynamic feel this is not something that static this is not a frozen body of knowledge this is something that researchers like Johnny and Kim continued to develop new ideas new reactions new molecules and dissolved unsolved problems and sent as this is about problems because there is a real need to build molecule and we've got the hint of sort of old-style were down a metallic chemistry we've seen green yard reagents and general lithium reagents we've seen how powerful these are as nuclear files and now we're going to see different ways of putting molecules together that in some cases are less pulsing logical in the since they don't necessarily exploit natural reactivity in the same way but they can stitch together what might be non-obvious bonds so I start by just mentioning the Bromyard reagent furor Negrin yard reaction just to just to take us take us back in so if you have enough halide allied we learned that if you treated with magnesium metal usually in serial solving Diana leverage at the furor and the magnesium
reacted sticks itself into this
carbon Alcalde flaws in the process it's actually going for magnesium metal oxidation states old Joe and alkyl magnesium here lies that the magnesium has an oxidation state of 2 when we're going to come back to that refrain but right now now I want a function focus on a traditional or get metallic reaction so it could take some Carbondale compound Keatonâ and held a hide alright it's generically as best it could be acetone it
could be could be annulled height could be could be any
other key tone and then we'll carry out mate with worked up usually when asked if you could use water to too if you really wanted to I think you Texas typically like to have something to add a probe talented the Oxy and analysts forms you formed a new carbon-carbon violent and if I
had to characterize this chemistry I'd say that the granular reagent for other
Rigano metallic reagent like inorganic lithium region of the so-called "quotation mark it's sort of a more general as mentality of the reagent acts is a nucleophile for carbon-carbon bond formation of the of the of the of the of of the is very
powerful because building up organic molecules really is a large part about of what's in is about forming cheek
carbon-carbon bonds controlling stereo chemistry controlling Rene geochemistry manipulating functional groups as you need them taking for example a secondary alcohol to achieve tone as you needed taking a key tone to an alcohol for reducing an alcohol down to a hydrocarbon these are all sort of standard transformations and a lot of the main processes that drive the building that sort of a layered on top of this the carbon-carbon bond forming agreeing what I want it to reduce now a different concept and I'll I'll introduce it in such a general way then I think it really is more a statement of philosophy at this point the particularly reaction but mansion for a moment we had
something a little bit different instead of transfer your nucleophile your group your or minus if you will to the Electra filed directly in other words just having the
metals as something that makes it so you effectively have a car ban the mansion for a moment now you have to ah groups on a metal and this is characteristic of the
chemistry transition metals really palladium is sort of the
the archetype of this although will see it with copper and then I mentioned that we sped out carbon-carbon bond in so long ago like Pierson also put parenthesis was getting your medal back in some
form so this is a little bit different if you think about it In the sense that it's not transferring the metal is doing something different than acting as a nucleophile a transfering and alkyl group you could say that their Donald metallic complex and this is an down metallic complex because you have metals funding into our alkyl groups of organisms responded to a metal you could say that their Donald transition complex act sort of light as a
template but but but but but but but but but but but but but to bring that you Tuareg groups together but but but but but but but the most can hang is a template for CCE von fermentation is a way this is no
reaction in particular will prompt the
particulars now really focus a little bit more mechanism when we see the Suzuki reaction but this is kind of a concept through
and 1 thing alone notice is the idea of a metal acting as a temp lights and the
idea of a metal acting as its
employees really ends up being about the mental taking itself out all the 2 are groups and leaving of bond and if you notice in a way this is the office said obvious step over here over the magnesium is sticking itself into a bar and has we approach this chemistry we're going to
see actions that are the opposite of each other oxidative addition which is a metal sticking itself into a bond much like we see with the magnesium here as I said increasing oxidation state from 0 to 2 and then the battle taking itself out of the bond which we call reductive elimination or get onto that more into in a
little bit so when I put as like together I wasn't sure how much I'd have a chance to cover
initially I figured we might get to cover section 20 6 . 3 that I've cut that out honestly I want you to get the flavor of the modern chemistry not all of the details here chapter starts with the really old were down a metallic chemistry organic food great chemistry so I'm going to to talk about that will talk about her dental group rate reactions and I wanted to talk about 2 Prize winning reactions this Suzuki the reaction from which we do in my advanced laboratories classes the beautiful reaction and a powerful reaction and the grub staff are well Woods technically often metastasis although its name is often associated with Thorpe's Grubbs the textbook in section 26 . 3 also talks
about the Heck reaction which is a little more conceptually complicated I decided to drop it out I didn't want want want us I wanted to this faces not entirely over here
Pirates selects there's let's start talking about a Danica cooperation but and now we got a tiny little
taste of organic copper reagents back in Chapter 20 and I think that's 1 reason it's nice to see them again so we learned this is all just write what I wrote in Chapter 20 we learn that we
could form Pagano copper reagents from reacting O'Donnell lithium compounds with the crew breasts all copyright died the salt compressed iodide copper 1 iodide is the salt you learned about the text of the spine so To equivalents of Anelka lithium plus Cooper's iodide CUI gives you all choosing EU allies flies if you want a balanced Europe equations lithium iodide as I've mentioned many a time organic chemists are bad about writing all right now right plus storage both them we call this an organic break reagents and if I wanted to write structure of this you can think of it as too are groups on copper with a negative charge on
attended the same theme as I talked about their and you'll see how that the incomes is in the chemistry that I'm about to move to introduce lithium is the
counter ion we call that's an 82 cooperate because when you have a negative charge on a species you quality and a cells this is a coup break because you have a copper miners charge and so some of the chemistry the learns about who praise was we learn they can modulate the reactivity in 1 4 verses 1 2 editions so we learned for example that if you hindsight will have seen all and if you trade it away as saying that the lithium the metal lithium adds to the Carbondale group to give an alcohol at this position if we train our cycle seen known however with lithium dime methyl who prayed the age of 3 To see you allies of the year Donald who plays reagent you get from adding that the lithium to groups criticized died and then you carry out make we worker I'll destroyed each 0 flights usually person would prevent invested in what's really special about recuperates is that instead of getting 1 2 edition instead of adding directly to the Carbondale group we get conjugate edition we get a Michael addition reaction and after work your product of the reaction is this really Mathilde cycle Hank Snow known and so already that
broadened the concept that copper had special reactivity unit brought in this concept of control and we see that concept of control with copper and other places as well for example itself again in Chapter 20 I introduced another reaction a special reaction of acid chloride C normally if
you'd taken acid chloride you take in with iron metal a metallic free-agent like international lithium reagent or graveyard reagent you can't control the reactivity if I taken acid chloride like and so we'll chlorides and I tried to add 1 equivalent of methyl lithium to wait to get a seat of Winona 1 equivalent of of methyl magnesium bromide it doesn't work because the resulting key tone is still very very reactive and so you get reaction to get a 2nd equivalent of methyl lithium to give to fennel to probe all and you get other reactions said anything with Ernesta here very hard to control the reaction to add just 1 equivalent of nucleophile but we learned the special reaction of cooperates sulfide take lithium diamond film crew parade Alright again 1 ch the region choose you analyze and then we carry out any previous work of what's beautiful about the cooperate chemistry is that we go ahead and we get a controlled single addition to unions seat and so that gave us a
new manifold of control people of knowledge about copper chemistry for a long time organic copper reactions have been investigated since well before World War Two were copper was discovered to modulate the reactions of green yard reagents and some of the fashions have you seen here what I want to do now is to explore 6 . 4 discuss another carbon-carbon bond forming a reaction that was developed later I think the 60's that gives us something that's less recognizable In terms of conventional nucleophile Electra filed chemistry in conventional nuclear file elect chemistry you can at least in your mind's eye say Well I can see the carbon meal is an electrified out the year battle group rate a nucleophile I can see putting them together in the conjugate edition and the Michael addition reaction you can also the 1 who will addition reaction you can also say
OK we learned any known was elected delegates the beta position as well as the carbon the opposition I can understand putting them together but now I want to show you another reaction on current the silver analogous fashion so you see what's weird about this on the convention for a moment that instead of taking friends so we'll chloride I take
1 course diary and I subjected to the same reaction
conditions lithium guy Mathilde could break followed by some sort of a witness worker with answer now can look at this as if this were green
yard reagents and you'd say Well it out vinyl chlorides of parents files we know that
while we sometimes can have to displacement by we're gonna metallic reagents in a conventional as central reaction for an example and as sodium a satellites also reacting with methyl iodide to get out related we know that
St till hybridized carbon Dole
participates in essence to type reaction and the act something very much akin to what I've written on your left hand blackboard occurs on your right hand last look here urea cooperate reaction your cooperate reagent does indeed react to
form a carbon-carbon bond and that special and that's where it all right a
which were covered in
parenthesis you textbook doesn't included honestly most people would do it the hydro lies the copper solved but unlike say
overreaction where you're generating an evil light as in the 1st place up on top it's absolutely essential
hearing a Rios work up isn't essential so you know you could say I don't care if I returned to my forehead so what's
happening here will it been hinting at this notion that metals can act as a temp template so in sort of a general since were having some sort of hair like this can be an alkyl halide it can be an arrowhead LID it can be a vinyl halide and were having some type of true break reagent so right this like so and what we're doing is we're forming but carbon-carbon bonds so as I said this is interesting because we're talking about alcohol primary and secondary you sometimes secondary al-Sayed primary metal for some time secondary over here alive but also final and own another recipient inferior none of this is doing a
reaction not only had things where you might expect the conventional lesson to displacement but also a lot of quite a lot of compounds
like this vinyl chloride compounds where you wouldn't expect a conventional medicine to displacement reactions I'm gonna say not innocent you are so what's that in
this chemistry of specialists chemistry is that the copper is mediating the reaction that copper is facilitating the reaction and not couldn't go into a detailed mechanism of giving Ontario mechanism for the Suzuki reaction but I want to show you just so that just let it that
copper accident in light of the but that in addition to having the 2 methyl groups around the copper but like during the reaction of the copper also attaches itself to the vinyl group basically just life just like magnesium sticks itself into copper into the alcohol carbon bonding forming a graveyard reagents the intermediate year-round which are drawn as such but maybe I'll put it in the bright just to remind us that this is not a stable home now that this is only an intermediate this intermediate forms and what it does now is the copper serves as a template for formation of a bond between the Mathilda and vinyl over the copper brings those 2 together very much like that sort of generalized reaction I wrote in the very beginning now as I
said this demonstrated and can occur card not just with typical sort of S 1 like alkyl halide but also
with things that would serve as into like doubtful he'll lights but also with things that would never never never participated in an effort into reaction and so 1 of the features with vinyl halides is that the reaction is serious business unit In other words stereo old chemistry is retaining about the bond of Alcatel hairlines but but but but but but but but but but but but but but for example I gave you has no it's very chemistry to the double bond but of course double bonds come in flavors assistant trainer and when you have 2 different groups on the ends of or 2 groups and the and 1 of the continent's in 1 of the other so if I agree imagine for a moment that we instead of having theologian at the 1 positions have been halogen had the 2 physician and novelist just for the heck of it bromides and again I mentioned that we subjected us to a appropriate free-agent just to show you some of the diversity of drew praise reagents let me give you a vinyl Cooper a region so I'll give you die vinyl true at 2 vinyl groups bound to work copper and then were not speech the Rio applause now what's interesting about this is we started with the trains area chemistry about this but we're going to transferred this final group over to this and we retain the stereo chemistry in other words the product but we started with Trans and we ended up with trade and that's kind of cool and kind of kind of significant so we're still trance and conversed slate if I started with sense al-Hakim and subjected to the same reaction conditions I'll just put it all hot here for the sake of saving and he's now we would get the others stereo chemistry in other words the stereo chemistry of the halides as dictated the stereo chemistry of the product last here were transitory the here were assessed were received sorry I kind of
wonder whether this .period summarize crew great chemistry and I'll just go ahead and since we see a lot of chemicals the lot of different compounds I wanted just show you may be 1 of of researcher would do
in the laboratory so let's save for a moment that the goal was just sit beside this
compound these types of vinyl compounds with chemistry about double bonds the present in insect Fair so you can
make a chemical compounds that will bugs by synthesizing their fair moans these are used to kill Japanese beetles and other sorts of past and so let's just take a look at what a person would do in the laboratory to the Wannamaker cooperate free-agent so they take a hell I'd like a vinyl halide and they treated with lithium metal member to equivalents of lithium metal is required to react with a to give an ordinal lithium reagent so I would get vinyl lithium was lithium bromide if I wanted to balance my equation in a 2nd step I would add Kubra sigh and die and if I wanted to balance my equation which as I said organic chemists often don't do we would take to equivalents of lithium iron diamonds and retreated to his life and I didn't get the recuperate reagents In the
final step is typically do this all in 1 flask you would make the lithium reagent you would add the copper iodine to make recuperation the organic
Kubrick reagents and now in the final step we would take part of styrene all worldwide and trading with our goal 3 free-agent maybe doing a Prius work off on matters of the that in foreign visitors from Europe but the together 1 of the questions
1 thing that's bad about 2 great chemistry is all the tools final groups on the tougher of the 2 are groups on the account you only transfer 1 of them so it's wasteful as far as the chemistry goes to waste half of your vinyl bromide in this chemistry another thing that's bad about the copper chemistry this properties of toxic metals and expensive beer-making medicinal compounds don't want any medals to be left and you certainly don't want medals are sticking Anetta better toxin so 1 of the things they chemists have been trying to do is
to make chemistry more efficient make it go by use of 1 equivalent of reagent rather than having to use to equivalents of reagents to avoid the use of toxic metals and to avoid having to use a whole equivalent of a metal that expensive more that's poisonous and to
just have that metal Temple act as a catalyst as I said cooperate chemistry was really developed in the 1960 s and sort of older Rosanna metallic chemistry and so I want fast forward us ahead now through what really on modern organic chemical reaction this is the the reaction of modern organic metallic reaction that largely achieved the same transformation In the beginning innovation of the Suzuki reaction while 1 of the
big innovations of the Suzuki reaction was instead of using an organic lithium compound that has a metal was to use an organic boron compound is that we've already seen that organic boron compounds a very easy access you can
access them by hydro operation you use them all the time in Hydro abrasion oxidation chemistry for is environmentally benign it's not toxic or are boric acid for example can be bought in the drugs stored in use as an eyewash it's not a harmful or poisonous chemical Lester cockroach in which case it's very good for filling them alright so the deduced that the Suzuki reaction the other big innovation was to use a catalyst to rather than the whole equivalent of men so we're gonna take something that looks very similar were gonna take Hale lied so often were talking of vinyl Warren Alpert on our own he aligned in some cases it can be an alkyl halide 1 of the active areas of research is making this Suzuki reaction more compatible with more different types of compounds are going to combine it with an organic boron compounds and typically the boron has a couple of oxygen is honored all qualities of all our client groups were not going to get into all the details all show you 1 later on this is an organic boron compound that's called the Byronic gas-turbine Byronic acid depending on whether they're helpful groups OH groups In the last piece of the puzzle it is organizers hope for a palladium catalysts now when
people write organic metallic reagents down a metallic patients a reaction often they want a focus on the big picture we're going to see that as we work our way through the mechanisms and
often their variations that don't matter a whole lot so I write this for also in or perhaps I guess since we're only focusing on the Suzuki reaction which is always done with palladium alright sub in PB and I'll just referred to this final give you an example of 1 in a moment but also referred this right now as the palladium catalyst and sell the in idea of the Suzuki reaction is that we're going to use the palladium catalysts as attempt place to come by the art groups on the border with the art groups funding here lies in the overall results it is drawing the former New carbon-carbon bond
very efficiently In my synthetic organic laboratory class
the students taking their junior or senior year the thing we do is Suzuki reactions a cool reaction they really enjoy it and the reaction they still is the take aid were almost diary read but that's been prepared for them by the teaching assistant in a serious specific fashion through elimination reaction is prepared by the combination of Namik acid followed by elimination and they combine it with an organic on reagent that they prepare themselves also in mysterious specific fashion by hydro operation with a world that has a lot like Esther that has but benzene group over here this is called a category called Moreno and the palladium catalysts that they use well I'm going to give you a variant of the catalyst we use of palladium to catalyst that I'm going to give you a palladium 0 plan was basically I wanted to to simplify some of it doesn't matter a whole heck of a lot which palladium catalysts used and wanted to simplify things a little bit concerned aligning them with your text and so the palladium catalysts that will use in this particular example is fabricated try panel past being palladium those tribes battled past themes religions on the Palladium they represent the lake shown over here and we're going to skip over some of the details when the catalyst is resting therefore try fennel fast being wagons around it when it's doing its thing of bringing the medals together there to try fennel fasting or fast things around it but that isn't so important but we also need base in this chemistry and this is typical of this city the reaction I've sort of written things in general form here in unbalanced equation and the product Of this Suzuki reaction is now just forming a new carbon-carbon bonds so we have to have that came from that help Tino hairline and a half of that came from our again award reagent with a double bond 4 H 9 group Bob Duval group over there so this is 1 of the 3 B 1 fennel 1 3 acted dying if you want to know the names of all right balanced equation them will talk a little bit about how the components form the other components of by-products if you will the waste products of the reaction are the the logic Esther with an apple groups of technically the boric acid derivative real boric acid as the derivatives and the other product of reaction is sodium bromide and just a reminder that we're using only a little bit only a couple of hours a small per cent of
palladium only about 1 mole of palladium 450 molds of molecules all right
that there's this is a catalyst here so I will just remind us of that underwriting CAT and with
abbreviation there what cool about this chemistry is it brings us to a new
types of reaction mechanism so it's cool because it's useful we can readily snapped together 2 halves to make a big molecules and the way that you really haven't seen before that's powerful but another thing that's cool about the chemistry is that it brings in some reaction mechanisms that you haven't seen before and yet have some familiar themes so I wanna break the mechanism down into 3 main that who is also 1 minor step that all insert went out I show you the mechanism in details Allstate 3 main step in the mechanism the 1st step is called oxidative addition in oxidative addition
the metal sticks itself into the outfield all lie behind into the carbon Hill on the 2nd means that these trends that alienation of the
Transmeta lations steps the other algae no group is transferred from boron to the metal and ventilation it kind of makes sense and almost says that in the 3rd 1 in the 3rd step where the metal acts as a temp flight and that's called reductive elimination of the metal spits out the carbon-carbon bonds and as I did he even
know you haven't seen organic palladium chemistry there's a a lot of analogy to a chemistry that you've seen and that's really what I want to focus on because I think that bodies of some of the beauty of this this very
powerful chemistry so as I was handing the line can go ahead and lose a couple of those strife at all fast being likened then so the active carrying catalyst is not detected cases tried fast palladium 0 but the best of try panel last being palladium 0 just ligand association reaction but don't worry about it like this then is the al-Zaidi the form of catalyst and technically that's going to be the species as we write the mechanism that we're going to focus on alright so this active form of the the catalyst can agree on this With the Alcatel halides so there's almost irony and as I said the reaction called oxidative conditions in oxidative addition reaction metal sticks itself into a bond and increases its oxidation state by 2 we have the carbon bromine bond we have the Palladium the Palladium happens to have a 0 oxidation state at this point when the Palladium 6 itself into the carbon bromine bond it increases its oxidation state to palladium in the plus to oxidation but right there will be needed but I'm not doing this you have be here are so we have to try Belfast since PHP pH 3 P 2 palladium now the palladium has the Alcatel group bonds found to have that
allied group found to it and even this reaction involves palladium even tho you haven't seen
organic palladium reactions before this reaction is just like the the formation of a green yards reagent in a green yard reagent magnesium starts oxidation state 0 you added into the alkyl halide bond now you have the alkyl group and the halide group down to the magnesium and magnesium said 2 oxidation states even the notion of Alleghany isn't very different when we talk about green yard reagents we said you have and the men in the ether solvents because the magnesium needs those ether oxygen as Lincoln's on it while palladium like hooligans then have more diffuse lone parents and conferred dissipate and other types of interactions fightback funding interactions and so as a result you have phosphorus the ligand rather than oxygen alright that's the oxidative addition steps before so here I I am going to again right our organic palladium intermediate and now analysis step occurs that's not super reported as far as this mechanism goes but it's facilitating the transfer to the boron we have sodium at side as the base but no words in terms of the innovative concepts it's not as much of an issue of this time plating process it's more of a mechanistic details of a alike and exchange reaction occurs that is at not side does basically what you could think of it as an S to displacement and kicks out bromides but I can't write this and the next line because the structures used for but there were going just replace the bromine within a taxi group and if I wanted to balance the equation I suppose I'd say that sodium bromide is also byproduct of this reaction OK now the next main reaction the Transmeta Leyshon reaction and so at this point we're going to transfer that group from boron onto to the Palladium in a way it's like another 1 of these acid into displacement sort of like reactions I talked about OK so here's our palladium species in this cycle and here's our organic on the founder of Byronic yesterday but of the In the structures here celebrating that I'm going to now move to the other blackboards and draw an arrow moved into new our air over
the the next morning maybe I will give the name here as I said overstepped his Transmeta lesions on the right during and as an ETA L. things to me I and we're going to transfer of the laden from the boron which acts like the medal to the Palladium but we still
have our supply group on the palladium and know what we've done is transfer are out penal group from the boron to the Palladium and again if I'm going to balance my equation the byproduct of this reaction the taxi group comes off the Palladium and onto the warrant for I'm really likes to the downtown oxygen because Iran has taken the orbital AT adamant that has long hair is climate is a friend of boron because those long periods only into the boron and so this ends up in the atop the group that we transferred before in the ligand exchange reactions ends up facilitating the trends ventilation reaction reactions final step is the reductive elimination step step in which the metal is acting as a so we have species here of pH very clearly styrene all but with our Algerian group and now In the reductive elimination it's the mechanistic reverse Of the oxidative addition as I've been hinting that again and again in talk with the copper and other things now we're going to take the Palladium out and form a bond between these 2 provinces groups of the but but of the of the of the of the overall result is going to be however I should write lower so that you can see it well from now we're going to have our Al Pena died in Oslo and are widening the 3 have 1 of the 3 1 panel acted after dying and we get back our palladium catalysts and dropped to the 0 oxidation state and this is really of course the hallmark of a catalyst the catalyst goes through the reaction again and again and again so the catalyst is available now to react with another molecule about penal halide staff have another ligand exchange to have another Transmeta Leyshon at her and finally to undergo reductive elimination again and again and again the dozens and even hundreds of times in the catalytic cycle let's
take a look and how we might use the Suzuki reaction in organic synthesis and I'll just poses
about sample question here let's say I was thinking about how we synthesized this molecule and I'll say I'll say Let's synthesized this molecule where we haven't got the honor benzene in a matter of conscience to a trends out penal group connected 2 a C 5 eights 11 a painting over so let's face it scientist nonmetallic from compounds containing 7 carbon atoms review but but but but but but but but but but but but but but but but but but but but but but but but but but but and if
you look at this cost side deliberately kept this kind of analogous because you're just beginning to learn this chemistry fight you might luck and say at all OK this doesn't look that different in other words we kind of get seeing how this case could come from an organic boron compounds and this they come from an allied and with all the chemistry that we know of find Longmire represent that downward and think
about things going backwards and I could say the managers that we formed this bond over a year In magic we did so the molecule into convenient have each of which has half the molecules so I can have Remgro moment vaccines and seeing as 1 half and I can't have any Byronic gesture of but as the other half like so that I can bring these 2 halves together so I guess I'll put a plus sign in
and say all I could see how I could do that by Suzuki reaction then you might say well lucky said 7 carbon atoms a few and I know we've got to many here because I've got 6
carbon atoms on this poor on the east 7 carbon atoms here while we were in the high corroboration reaction we've learned that its specific and so you'd say I can't imagine warming His find here by Igor operation and we can think about words and more and say OK if I hide reverberated with 1 of time and reacted with Tadic told boring already have hinted that that a readily available or dental boron ,comma now that also conveniently contains fewer than 7 carbon atoms now I can't imagine Tiger operating peptide in area specific factors to give us the France compound combining it with my from our aromatic
Institute the reality is that I could put this all together in Poland's since so far
enough forward said sort of solving our synthetic problem start with that kind of hybrid berated with tadpole Rangers mix them together the if you really want to make the reaction going quicker that gives us the the 5 age 11 healthy the normal for rain arraignment the myself then I could imagine combining that boron compound but but but but but but but but with the In of little moment that seemed seeing which we will talk about how to make but fortunately I have given you a chemical supply house that provides chemicals up to 7 problems you know how to make it from your mean chapter but you don't need to be because I've given us nice chemical supply house they will take our tepid kits supplied dental floss Feinstein palladium catalysts a consortium of scientists at the catalyst over here just to remind us we're only using a little bit and full equivalent of sodium and not size and the overall result now is that we have synthesized the target molecules of the than the because of the power
of this chemistry in 2010 and Suzuki won the Nobel Prize for this along with the and also with that we've had who invented the heck reaction that we're not going to talk about said this
is really powerful and useful chemistry for forming carbon-carbon bonds so 1 of the journals I like to read is the Journal of organic chemistry journal work of organic chemistry is worth people published contemporary organic chemistry research and they're usually dictatorial abstracts in the journal so you can see what's going on in the articles you can learn more about what's going on before you read the entire paper that it seems that I can't pick up a copy of the JOC of The Journal of organic chemistry these days without seeing at least a couple of examples of the reaction that'll show you next reaction of all of metastasis that 1 but rather to make sure that the Nobel prize fighting 2005 so but the at the the and
metastasis for a long time had been an object of curiosity just a weird reaction in
an organic chemist notably grubs and Schrock started to try to exploit and to understand the chemistry and here is what we have today suggests that the chemistry all right it's sort of a in SMI general terms but not a full in general terms because there's so many variations suggests that the chemistry is that we have to allergies but at the same were different depending on some subtle subtle issues and any ruthenium catalysts and get a ride out the structure moves show you a little bit of a flavor of the mechanism of it so all right it's again sort of the general way we did when we started to talk about the Suzuki reaction LAN meaning legions on the metal over the medium of where the metal ruthenium is bound to and now working group and again on their right fists as calm and when you have a job that's doubled bonded to a metal new quality metal being and so this is called the Ruthenian Kirby catalysts of the catalyst that these days is in his used is called Grubbs catalyst of after Bob Brown and because this
is such an active area of an research in his laboratory there's a 1st generation Grubbs
catalyst the second-generation Grubbs catalyst the third-generation Grubbs catalyst as well as probes evaded catalysts and other other variations of it but the main thing the main feature of the Grubbs catalyst of the Ruthenians are being catalyst is you have a medal double bond is part and what this metal dies or is it participates in a very amazing partner swapping and in this partner swapping dance the metals swaps partners with the alpha female groups and ultimately the groups smart partners but with each other and again writing this sort of in a generic fashion and then-deserted various variations on it we get a new well team generally is a mixture of Sisson trans isomers in which the 2 original AL teams have now joined to each other they could be the same or different during a molecule that sometimes the fans and the other piece of this partners swapping in the way that I had written it is that you get a molecule of baffling and typically
sends ethylene if the gas goes away and you basically know kept the main parts of the molecules together let me give you a specific samples because it's
a little hard to to kill absorbed in the vast generality there might take the molecule 1 the next scene of like cell and I treated and I'll show you the grubs first-generation catalyst honestly bravura purposes that's all you need to hear the legends on the metal
we've already seen legends of halogen ornamental we've seen legions of phosphorus on the medal here we're now seeing awakening of car on embattled The Grubbs catalyst has a couple of chlorine is
on the metal in has a phosgene and typically the Feinstein is tries cyclone on-screen and there were 2 of them down to the ruthenium and then went on and drawing out the 1st generation Grubbs catalyst has a benzene group over here we we only use a little bit of a catalyst to Lieutenant swap partners Delaware evasively gets walked out of a catalyst in the catalytic cycle on remind us this is a catalyst and they all product of the reaction that is we're going to to join our to scenes together and blow out a molecule of ethylene which is going to give us a molecule of flight testing so if you can count to 10 and just trying attend carbon chain here 1 2 3 4 5 6 7 8 9 10 analysts say is a mixture of assistance trans isomers of typical late win loves reaction goes into trouble accurately enough show show you an example of that at the end you just get isomer the murder because of the constraints of the ring and typically if you have just to our culture and you get a mixture of assistance Koreans although controlling this area chemistry is the key issue so we ever refined gasoline plants happily and I think what
we realize more loves is genius here contract and even before that I think is named Michel band as well as Tomcats she was sort of the 4th man on the Nobel Prize to almost 1 and I think what worked all of the genius looking at this reaction is the idea of saying Wait a 2nd I haven't seen anything like this
sort of partners swapping war and recognizing something is unusual whether it's in chemistry or if you're going on to become a doctor or a medical researcher whether it's in medicine or whether it's in pharmacology and saying Wait a 2nd best doesn't fit the mold of what I've learned recognizing that gave the grounds for big discovery if you're in the area of understanding sort of basic science you say I wanna learn about it because I've never seen anything like this if you're in an applied area and synthesis is or will that basic science and will that application of fury applied area you say it always has sacked and maybe I could use this discovery to do something maybe I could figure out something useful as an application of this established show you the gist of the partners swapping mechanism and then maybe walked and a couple of applications and sent so did just that all of the partners swapping mechanism is can you have your room the new car being tripped on just the right as I did in the very beginning L and R U double bond is to win out little and you're ruthenium being reacts with another Al-Qaeda given on the tellers cycle of butane I can draw arrows like this like a cycle of addition reaction I think that's probably for how we're going to think about it a lot of times when you think about her down metallic chemistry ones focusing more on process and on mechanism in other words in essential Riexinger thinking very much about the mechanism of the to inorganic metallic reactions you thinking a little more about a process in other words were not wearing exactly how an oxidative addition occurs we're just looking and saying it it turns out OK so now we do the exact same thing in reverse in other words this is a sort of a cyclo addition reactions now we do the reverse and we end up going enough or are you double bind to CH to grow and the other product that we've flown out of the reaction is our our Al-Qaeda loops and I'm not worrying about Syria chemistry here so that's our outfield groups if you don't like my writing hydrogen is in here and tell you what titles -dash right this is the people fervent basically I'm not passing on whether it's a sort stereo chemistry OK now all the partners flopping
and in the 2nd step so we've flown out hand and now we have had a car being where we have our
ruthenium bound to win this Philogene group CH 2 group and now in the partners slapping we have another molecule all of our AL teams coming in and again we're going to make a cyclo addition reaction White said of the Unabomber Tello cycle of butane lighter snow and now we do the reverse of the cyclo addition reaction and we blow out a molecule of ethylene and we didn't back our carving and this cycle continues over and over and over again as we drive the reaction blowing out ethylene in driving because of the fall so as they did
before this reaction often is used when two-out teams are the same molecules to make a new rate we've seen lots of rings reaching brings in steroids other sorts of rings and the ring closing metastasis is it's called Oresteia animals is a particularly powerful way of making Lane installed diagram this sort of in a generic fashion versus where we have to al-Hakim's group
connected by some sort of tether and we
subjected this to cattle to art catalyst and again I'll use our first-generation Grubbs catalyst again the details or something which catalyst you'd use in which circumstances probably go a little beyond the scope of the course and the overall result of the process now is to swap partners on the 2 ends of the range of 2 of the people like out conforming to bring down the middle new
textbooks gives a nice example and then
I think maybe I'll take 1 made to show you out of an example of our thinking process said textbook shows this that this is the proper role of being reined in which it starts with Al Amin that has the task of group nitrogen is subjected to the reaction conditions but then we formerly of tribe members during and I think
that's kind of a nice nice starting point for this sort of problem that I think you should be able to solve I tend to think about so let me show you show you what I may be a thought process would say let's
say I want to synthesized site will have to you With an alcohol there been a double bond then let's say just to put some constraints on all safe from compounds containing 4 carbon atoms you feel but but then just to give us maybe a little hint housing using old-fashioned metastasis are now you look at this molecule you look at the example 1 that black words and you say helped all I can kind of see my way back this is represent the attic analysis and I've given you will begin wearing head to say I can't see my way back to a compound in which I have since forming a seven-member ruling were bringing together 1 to brave and was to sorry I can say 1 2 3 4 1 2 3 4 1 2 5 just imagine bringing these 2 partners together to say I can see that and then you look you say Well we've still got a lot of problems in here and you say Wait a 2nd hole camp thinking back to down lithium chemistry and I know that I can go ahead and had Tuesday and asked groups To equivalents of inorganic metallic compound like a lithium compound and I can use any sort of gesture like the and now you put this together you say OK I can go ahead right in fight go ahead and say I will take let's say they don't make Myra down lithium compound just for the hell of it principles might parameters didn't require this that I will take the let's say provides almost compound I'll take my them or helping with 2 2 lithium is that this kind of ends up being a refrain for all the things we've done in the class and make an Rigano lithium reagent we've taken our ethical Astor that's going to be the top 2 parts and we treated with 2 equivalents of the began lithium reagents Santos said organic lithium reagent for foreign is to equivalent and then I do in a separate stepped on we work and that's going to take us over to on building block 2 now I have taken us all the way and I just objectives during closing metallic assists which I write as em and I have tried and it's that type of thinking that can lead you on your last question you have put you use magnesium someone answered yeah I awakened going at major train yard reagent Pennsylvania we've gone in the course of all From green yard and Ravenel lithium chemistry through Carbondale planners parade through I mean chemistry through the Grubbs reaction to to build really complex molecules from simple building block you guys are the greatest knocked them dead on the
final I will stay on
until Tuesday while they wanna be allowed


Formal Metadata

Title Lecture 19. Organometallic Reactions in Organic Synthesis.
Title of Series Chemistry 51C: Organic Chemistry (Spring 2012)
Part Number 19
Number of Parts 19
Author Nowick, James
License CC Attribution 3.0 Unported:
You are free to use, adapt and copy, distribute and transmit the work or content in adapted or unchanged form for any legal purpose as long as the work is attributed to the author in the manner specified by the author or licensor.
DOI 10.5446/19423
Publisher University of California Irvine (UCI)
Release Date 2012
Language English

Content Metadata

Subject Area Chemistry
Abstract This is the third quarter course in the organic chemistry series. Topics covered include: Fundamental concepts relating to carbon compounds with emphasis on structural theory and the nature of chemical bonding, stereochemistry, reaction mechanisms, and spectroscopic, physical, and chemical properties of the principal classes of carbon compounds. Index of Topics: 3:52-Grignard Reagent 7:01-Organometallic Complex 12:47-Organocopper Reagents 23:05-Organocuprate Mechanism 25:17-Stereospecificity 32:02-Drawbacks of Copper Chemistry 33:55-Suzuki Reaction 42:48-3 Main Steps to the Suzuki Mechanism 55:37-Using the Suzuki Reaction in Organic Synthesis 1:03:00-Olefin Metathesis 1:11:16-Partner Swapping Mechanism 1:15:20-Ring-Closing Metathesis

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