Lecture Stoechiometric Organometallics 13 - 26.11.13

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Lecture Stoechiometric Organometallics 13 - 26.11.13
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13
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22
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CC Attribution 3.0 Germany:
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2013
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English

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Abstract
Metal-specific features: Magnesium -- Magnesium-Ene Reaction
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Metal Übergangszustand Setzen <Verfahrenstechnik> Polyvinylpyrrolidone Terrasse <Geologie> Aspartate transaminase Wursthülle Chemical reaction Aromaticity Alkene Systemic therapy Magnesium Deterrence (legal) Taxis Electron Cycloalkane Transformation <Genetik> Process (computing)
Stop codon Übergangszustand Ionenbindung Wursthülle Alkene Magnesium Human body temperature Cryogenics Transformation <Genetik> Methylmalonyl-CoA mutase Organic food Process (computing) Area Substituent Setzen <Verfahrenstechnik> Hydride Doppelbindung Carbon (fiber) Topicity Addition reaction Chemical reaction Alcohol Induktor Propene Systemic therapy Hydrogen Acid Functional group Chemical structure Cobaltoxide Paraformaldehyde
Setzen <Verfahrenstechnik> Übergangszustand Reaction mechanism Walking Rearrangement reaction Addition reaction Chemical reaction Alkene Reactivity (chemistry) Magnesium Systemic therapy Hydrogen Functional group Human body temperature Methylmalonyl-CoA mutase
Übergangszustand River delta Biosynthesis Oxygenierung Chloride Organische Verbindungen Leak Aromaticity Alkene Alkaloid Magnesium Ageing Film grain Transformation <Genetik> Oxide Process (computing) Naturstoff Stickstoffatom Rock (geology) Allyl alcohol Oxycodon Walking Rearrangement reaction Carbon (fiber) Carbonylverbindungen Alkansulfonate Chemical reaction Alcohol Erdrutsch Systemic therapy Water Hydrogen Gesundheitsstörung Functional group Chemical compound Chemical structure Cobaltoxide Hope, Arkansas
Metallorganische Chemie Chloride Operon Finings Alkene Isomer Protein Colourant Allyl Transformation <Genetik> Organic food Hexane Condensation reaction Dye Doppelbindung Concentrate Octane rating Alkylation Walking Addition reaction Chemical reaction Solution Systemic therapy Branntwein Azo coupling Chemical compound Biomolecular structure Stuffing Stop codon Biosynthesis Plant breeding Oolite Titration Methylgruppe Magnesium Nobelium Human subject research Cerium Hydrolysat Molar volume Cryogenics Lithium Oxide Process (computing) Naturstoff Setzen <Verfahrenstechnik> Metal Selenite Ketone Carbon (fiber) Pascal (unit) Hydrogen Combine harvester Gesundheitsstörung PH indicator Functional group Radical (chemistry) Chemical structure Base (chemistry)
Phenyl group Carboxylate Hygroscopy Wursthülle Titration Molecule Colourant Molar volume Orange juice Tool steel Lithium Monoamine oxidase Process (computing) Setzen <Verfahrenstechnik> Butanol Doppelbindung Concentrate Deep sea Protonation Solution Biphenyl Alcohol Gap junction Systemic therapy Hydrogen Combine harvester Drop (liquid) Acid PH indicator Functional group Etomidate Iron Base (chemistry) Thermoforming
Weinfehler Residue (chemistry) Precipitation (chemistry) Separation process Species Titration Neutralization (chemistry) Deterrence (legal) Nobelium Colourant Hydrolysat Molar volume Lithium Solubility Process (computing) Waterfall Setzen <Verfahrenstechnik> Bromide Octane rating Chemical clock Addition reaction Solution Hydroxide Systemic therapy Lithiumhydroxid PH indicator Functional group Chemical structure Base (chemistry) Cobaltoxide Bottling line
Setzen <Verfahrenstechnik> Metal Residue (chemistry) Surface finishing Titration Solution Chemistry Deterrence (legal) Water Lithiumhydroxid Ageing Cerium Singer Corporation Aage Base (chemistry)
the you hit the ball Our come to
lessons 13 obstacle metrical Organometallics said today be stopped the metal specific features magnesium and so in focus 2 dates especially the so-called magnesium EU in reaction so we will see what that 1st of all you will certainly remember the general scheme of the Diels-Alder reaction we have a dying and an olefin and it reacts in that concerted terraces to form the cyclo taxi that's modified the dying component simply such crop clean system and now imagine the concerted process Walter R. K. let us explain at this very aromatic transition state in this case involving 6 supply electrons electrons so here you can also imagine the process where 6 electrons take part too often forest electrons or is it more electrons it could give this result and this type of reaction indeed works and it's called the in reaction self Let's have a look for examples the thermal induced transformation orcas just as in the general
scheme the C-C bond is formed while those 2 C C double bonds of transformed and single bonds 1 hydrogen is transferred and here the double bond is formed It's the same here in this case this hydrogen is transferred to this position the C-C bond is formed between this and that position to give a double bond is formed so this is a no nice example of of the in the reaction and would be ruined areas that as this is a concerted process the group's option inferred from the same side to the same side of all of the so that means that we will have the 5th product the haven't what selectively unfortunately in this case you to rob a high temperature 4 100 50 degrees there are 2 examples where we have a low temperature this 1 for instance this is the allylic system the most interesting this money and hydride is also known as a very good to die in file induce other reactions and indeed also the mean reaction works very well in exciting at reflux so approximately 100 40 degrees resulting in this product by the way you might to notice that after our starting allylic component there is the terpenoid notre product this is better finally well that's modify this general scheme a bit
more the state of a system like like backed this of propene system to hear the change from 1 C H 2 group to an oxygen so reaction there is such a system of the cover line does this transformation work yes that works very well especially if we activate the carbon I drew by the Louis acid off might also be a car is faster than you could introduce some occurrence centers and serious selectively when we have some additional substituents this type of reaction there is also some kind of the reaction that carbon lies in the reaction what again that introduce small change here put an a magnesium hated instead of of hydrogen so you could call it that the Coburn Meyer right immediately on being reaction but to the wall this on name is not usually applied know but there's there's in addition reaction to a common I group of organic magnesium and this is the typical green yet reaction while the bit 8 topical because also this reaction proceeds through the 6-membered transition state so after well if you have and Allen magnesium compounds then there are areas of equilibrium It's been those analytics structures and the equilibrium it is by far on 1 side of the less sterically hindered to undo magnesium component so that means even if you start movements bromo all 14 you would however this as the main component in the reaction for instance formed elder hired the who is specific magnesium coordinates to the oxygen and then while this is the stop for will formation of the 6-membered transition state and as a very narrow to this this is indeed the bit funny although with this the main structure of the magnesium compound in the equilibrium final product this alchohol looks like that too is that it to or at that derives from the 1 to reaction of this starting on how to make magnesium so finally that change the general scheme back from the problem I just to an olefin sorry there is something wrong that's the reason why it Doesn't work so yes now it's
correct OK so this reaction than being a reaction where we have change 1 hydrogen to magnesium pay died and this was then called the magnesium being reaction as the general scheme
and of course this groups otherwise it wouldn't have done this our introduction so 1st example of than in terms of molecular the museum in reaction verve on especially reactive olefin since it's a strained olefins so in by default the you through temperatures that 0 and 20 degrees the dean reaction root of course and again certain in addition reactions what essentially you the to use the also of cobble magnetization but with a special mechanism concerted mechanism of the 6-membered transition state and to well might trap that from electrophile and you figure out that this step proceeds the the ballot AT T 5 per cent a year for the intramolecular magnesium even reaction they're all 3 types type 1 the ring closure reaction queries and all olefinic parts all the oriented exercise this this type 2 1 olefin those 4 oriented and psychic and ring wall and to type 3 finally than all olefinic parts oriented and selected resulting instructions like that so on the following we'll see some examples in addition a remark as you notice more electron-rich the system so all very often of the lower the temperature of it is necessary to to activate you know that from the other examples well you might the the cult rearrangement this call prearrangement needs while about 100 80 degrees on
such protests you our coordinates falls within congruence they also all undergo but cope rearrangement finally leading to these structures delta epsilon unsaturated carbonyl compounds and since this is a more electron system this also in chronic come tact of course the further the 6-membered aromatic transition state on the reaction procedure as much the more moderate reaction conditions about 50 to 70 degrees are sufficient for the so-called oxy rearrangement but the back to the magnesium being reaction some examples South what would be result of that here the six-member transition state bring closure reaction from this common to that 1 I think it's very easy to understand introducing such the reaction step as the key step in natural product synthesis and most of these natural product syntheses have been Our performed by the group of a pulse I think in own and hope that's right so here by the key steps the magnesium in reaction this key step low carbon skeleton all in all of what's called sky sky 10 theme was synthesized already at minus 4 the degrees 16 hours reaction time the magnesium union reaction of cruise of this system It's deRiel selectively an addition 1st process and an oxidation both claim to be done just before oxygen introduces the alcohol so the the next step now I'll call functionality is introduced here should be clear for everyone from organic chemistry to not to this was of call so the addition of water and and onto Markov Nicholson's to an olefin and to the for the snaffled for that this slide reverberation and oxidative so this th 3 and then 2nd also to hydroxide basic conditions with the hydrogen the rocks on so
or getting to the target compound it's an alkaloid we have to introduce the nitrogen functionality wall it's clear that we need to Knuth to muscle from mean pass the file so secondly I mean 5 and 1st of all we have to transfer through useful age group into good leaving groups and this has been done the part sulphonic acid chlorides when we need the reading and connects with old synthesis to this natural product the another synthesis to a tap annoyed called companies and here the ruler and all to introduce that a lunatic magnesium 80 light very straightforward if you trade this al the height 1st by Leslie of well I should write down what you get them you get this allylic alcohol secondly treating that the 5 New crawl right wall exchanges legal age against against the chloride and at the same time rearranging this system and here we have now a leak right so our this two-step transformation was successfully done that of 76 descent activated magnesium performance the grainy at the reagent now we have that are nicely set up for the magnesium reaction so in addition process as usual so and now are crawling those added giving again the allylic alcohol the unit achieved laws 57 per cent so what what might be the problem here why is it
only 57 per cent Our OK you always have some some problems with that information after a liquor magnesium pay lines of it's not activated enough you have discussed that problem of allylic radicals as intermediates before the other problem is this step certainly because you have he is want to reaction all of on competing there of the conjugated addition reaction 1 fool addition reactions what we will learn tomorrow but you can solve that problem with a trans methylation you should do change to organo cerium to get a nice you'd for 1 2 editions process we will discuss that indeed to tomorrow so again we have oolitic Alcoa system and wall and enable it this olefin that process the transformation to and Alec chloride and then the other forming the agree reagent again there's repeated 72 per cent for that step and then well costs of magnesium in a cycle isation persons so should be the type 1 magnesium even cycle ization great oxidation it was the next step or alkyl functionality than the short sequences we don't need the details having all died and the keto in there well clearly this has been oxidized that and maybe granular in addition reaction oxidizing again that we have that Knuth Keaton on that side on the other side the olefin transforming to re l the height this is of course done with the nose and all of this so but now treating this compound with the base Aldo all condensation reaction the number I've membered ring is formed the so that's right down target compound to couple the leading here the X a sidekick double bond so while we could just guess will be what will be when the force of choice for getting from here to there true steps will 1st back that is to reduce that double bond had a nation under of appropriate to reaction conditions and if a carbon my group to transform that to get psychic double bond this is simply that the tissue the so 1 longs natural products synthesis from a pulses group once again the strange names in René structure of the target compound as this so once again the key steps at this Nobel I mean system there's the intramolecular magnesium in reaction what I've found interesting is that up also introduces the capitalist for the formation of little green yet reagent and the catalyst this to small per cent of something you already knew you already know that magnesium enters complex 2 more and enough to capitalize the formation of the going Europe reagent so this reaction
was performed at low temperature 170 degrees and the magnesium being reaction cruise while warming up and it's in addition process what the carbon skeleton is almost set up we need of the 1 one-carbon component maybe simply you form all the all right here on the other hand and isomerization from Avi and a position to be X a position of fine of you guys would preclude group has to be achieved OK but needs a couple of of more steps but I think the principle is clear another subject for today is wall then no you are preparing argon Elysium organic magnesium compounds all 4 of these bases like LDA retreat off you need to know what the quality in constant the concentration and the quality of Europe organo metallic reagent also of cross if you just only by your boot to this it is so 1 point 6 molar solution in hexane and others in the group might have already used it and maybe we were not to the back half full in avoiding the moisture and hydrolysis and sooner or later we will be in need of testing the quality of furor organometallic reagent this is normally done by titration you will find a lot of pursued procedures to do that and a lot of indicators and let's have a look for luck look on some of those indicators self subject it is tight rating when reagents all gonna this grandparents and to a wall also strong bases like Pelletier 1 nice indicator which works for all of those created regions although this and combines and LDA is mistake what you can easily synthesize this because it's simply the fund hide zone of the solid slick a lot that's it if you did protonate there's with a strong base your cost approach 8 of the most acidic position and this is the phenolic hydrogen if you do so the titration means of a certain concentration off that component and did you add other original gonna this the that it would be to protonated so 1 the cruel and of the strong based the Greeks and so on please keep in mind that the green yet regions are generally fall last basic that are gonna lithium compounds how ever Green yet regions of basic enough to do crotonate here and they also are basic enough to the protein at a 2nd time decided so 1st of all the solution turns yellow and it keeps the yellow color which becomes a bit deeper and deeper and to you have added 1 pick verbal of all the stuff you want to test so 1 dropped more of strong base the stop to produce the dye and I am and this has another color the chance right so having a 1 molar solution of that and tied treating and or another you have to know the molarity of your solution and to while finding out what is 1 equivalent can do that by this operation 1st crop and you have that the turning point OK it's not that nice the change from yellow to rent be better if you would have the change from colorless to something never seen indicators but do that job the following however these indicators doesn't really the organic magnesium compounds you need strong bases to deprotonated those for a 2nd perform the dialog so 2nd example as I said this work doesn't work birth got a magnesium but the LDA and the organ this so what it's saying want the commit will of are gonna listen so and this time the Haida zone hydrogen is the most acidic 1 all OK of
course activated by the tosyl group and again 1 drop more then from colorless mono an iron the gaps to this annoying Dion client so here the fumes component and which is yellow at low concentrations wrapped at higher concentrations so as soon as the 2 and red you have further push look over tight treated the system two-loss similar very similar examples p-value you lights most acidic position is the amide proton 1st the protonation before 1 equivalent 2 comments the upfront 5 or hydrogen or was the phenyl group 1 drop more of a strong base learn deprotonated in at position or if it's a phenyl group double bonds of position and this 1 is yellow in the case of Our prime the hydrogen or yellow to orange the phenyl very similar the next 1 but a bit newly introduce also up way the advantage of this system there was that the 2 is less hygroscopic that can other indicators and you might imagine it's not good to introduce the that indicator well this titration process so also rather non hygroscopic 1 this is 1 works very similar to 1 before 1st deprotonation and 1 dropped more so you then 1 equivalent 1 group more the dire 9 this form all of this methylated down and it then select position and here the change in color is from colonists to a nice you which is of course are easily noticed the same principle although not very much related unless the fact that you could also do protonate this diphenyl acidic acid twice 1st deprotonation forms the simple this year carboxylate and the 2nd 1 the corresponding you know knowledge change in color from colonists tool know an interesting case there's this 1 try Sandel the frame deep protonate in right funnel the thing gives somewhat pink color but how can you type tweak that having but triphenyl the faint solutions and adding to the theorem strong base will give immediately the pink color so the trick is you need a system which you can be twice and the phis 2nd deprotonation you get the formation from that color so very simple just what then another component doesn't give the color but this is to be deprotonated now found this this done the 1 molar solution of an article and a little bit of such an indicator that's it essentially It's the same as we have seen before but there we have that those so too acidic positions in 1 molecule so with ISA butanol there is no 1 hour which is often used and the other 1 that is so used wall nowadays I think even more often because it's less on the hydrophilic this is mental so that the
1st deprotonation protonation form of the lithium Cobol named and still however that indicator untouched 1 dropped more you still have lithium correlate but you start to form on the indicator and you will get there for and it response the color response of the system the combination of an alcohol and then indicated sorts of often done live
I've our financial being all or they have to to try and died through doing what to reduce this 1 the same process the same principle as before the you can type trade several times the same solutions you have a turning point well maybe add the little bit of of call for neutralize it amounts simply start again so then and the color change here in this for this type there's describe that in the key PD euro as back that lithium skew late by of the but the written system and should be essentially the same for untrue truly system it's claimed that this has the deep color indicating that while the redundant point while I am very much in doubt that this is correct since there ears the so called Ireland titration which bidders specific for I might basis in presence of correlates spend hydroxides and for the Ireland titration the indicator this formed so and which would assume and go to this undergoes an addition reactions to this by prudent system and certainly also to the on this the natural system and this has as described by Allen Ireland that doomed what a rat to group color What's with hydrolysis the colors indicate and this indicator that there's specifically deprotonated I am I bases in the presence of a hydroxide and accolades as I said before the structure was proven because oxidizing it when a clock oxygen the 1 the two the two week problematizes oxidative the this way I'm pretty sure that what's in that case for for that titration feel cool and and that Rouge color red bluish color derives from that and not from from that of its so this is an overview on of the Bauer Day the faults all single titration these net faults have a disadvantage to tell you something of somewhat reliable about the concentration of valuable to lithium orthogonal museum in solution that doesn't tell you anything about the quality remember you start many by at the 4 1 comma decimal 6 molar solution of opportunistic after a while some people have used it the bit is hydrolyzed maybe more than 50 % might be hydrolyzed and the wall than a white precipitate this fall and the fin that your flask more than the the bottle and this derives from the lithium nevertheless there appears solubility of lithium hydroxide in virtually exane solution there might be wall 10 per cent of lithium hydroxide in that solution and this is bad quality while 3 per cent of the lithium hydroxide is so wall normal to put quality so that means you might have in solution residual base but if you might excite hopping you determined that it might be necessary or a good idea to determine and this is done by the so-called go back and double titration 1st titration very simple the take while the ballot to a 1 milliliter of solution and hydrolyze it did you hydrolyze it and then you would type trade but that the gains to for instance phenolphthalein as indicator indicator their further 1 will our hydrochloride solution I typed rating this you'll get the total base content of the trouble your test such total base the simple
titration secondly you treat it that were to soon the Open Access 1 to guy bromo the thing what will happen more elucidation forming good to remind and this on order it'd species which of calls eliminates this room bromide forming the same so you have destroyed Nobel to the
student this formation and base so you expect that with water that having all the lithium hydroxide all that residue Bayes that and of calls when water solution you type trait again and that's where it to figure out to the amount of residue you should do that 3 times that makes for wall 6 titration that you have the reliable results this explains why they use on in singer titration of metaphor so our prefer to of all all of our all so those not affords you should do do on 3 times for getting the so the the old Guillemin titration you get additional information about the quality of your organometallic Piaget I think this is important to keep in mind Our finish for today and tomorrow we go on the 1st of on metals specific care futures and tomorrow will be about organo cerium chemistry Fig. voters fortysomethings you tomorrow the you hit the ball
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