CHEM 2332H Lecture Notes - Nucleophile, Diisobutylaluminium Hydride
15 Jul 2014
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From last time: carbonyl groups, electrophilic @ carbon. -> nucleophile will add either above or below the sp2 hybrid plane that has the c and o and other bonds on c. If attacks from other side, inverts stereochemistry --> can get either enantiomer/stereoisomer from this rxn. Synthesis: with 2 negative o atoms, doesn"t really want another negative charge coming in and attacking (coulomb"s law) --> need powerful nucleophile like organolithium to do this. This only works with organolithiums, thoughnot as easy to prepare as other nucleophiles like grignard reagent. Al also has 3 bonds like boron usually don"t isolate this. Will learn what happens to hydrocarbon, but not how al decomposes. Acid chlorides and esters: most hydrides = strong enough to deprotonate carboxylic acid --> h2 gas. Ochem page 3 first need to convert carboxylic acid --> acid chloride (after workup) Ester = better electrophile than carboxylate b/c don"t have h at one of the o"s relatively stable intermediate.
