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Unformatted text preview: Draw a mechanism for the following reaction, showing all intermediates, all curly arrows describing electron movement and all charges (if applicable). N H H 2 O + H + H 2 N O H : HN H HN H OH 2 H 2 N H OH H 2 N HO H 4b (6) Use the appropriate pKa equations to show why LDA (Li diisopropylamide, pKa diisopropylamine 35) can be used to quantitatively deprotonate a typical aldehyde (pKa 19). DiisopropylAmine + H 2 O = Diisopropylamide + H 3 O + K = 10 -35 eqn1 Aldehyde + H 2 O = enolate + H 3 O + K = 10 -19 eqn 2 Add eqn 2 + reverse of eqn1: Diisopropylamide + Aldehyde = Enolate + DiisopropylAmine K= 10 +35 x 10-19 = 10 16 5 (4) Synthesis. Show how aldol reactions can be used to synthesize the following α , β-unsaturated carbonyl-containing compounds. Show the intermediate aldol formed in each case. O O O O O HO via O O via O OH...
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- Winter '08
- Carbonyl, Keto-enol tautomerism, corresponding enol tautomer, Li diisopropylamide, H2O H+H2O H+H, following reaction Br