Reactions @ a-Carbon

Reactions @ a-Carbon - Chemistry 342-2008 Mukund P. Sibi...

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Chemistry 342-2008 Mukund P. Sibi Reactions at the Alpha-Carbon of Carbonyl Compounds C O C H C O H Aldehyde or Ketone Enol OH H + C O H Enol Formation of equilibrium amonunts of enol Reactions of enol with electrophiles C O C H C O C H Enol Nucleophilic or electron rich E + C O C H E C O C E O Br 2 H + O Br Pyridine heat O Examples C O OH 1. Br 2 , PBr 3 C O OH 2. H 2 O Br Hell-Volhardt-Zellinski Reaction O C N Li LDA THF, -78 °C H O C carbon nucleophile E + O C E Complete Formation of an enolate O C Enolate Alkylation C X + O C C S N 2 Enolate Ion Alkylating Agent + X - H 3 CO C O C C O OCH 3 H H NaOCH 3 CH 3 OH H 3 CO C O C C O OCH 3 H Dimethylmalonate Na + Sodio malonic ester R X H 3 CO C O C C O OCH 3 H R Alkylated malonic ester Monoalkylation of malonic esters Dialkylation of malonic esters H 3 CO C O C C O OCH 3 H R NaOCH 3 CH 3 OH H 3 CO C O C C O OCH 3 R Na + Sodio malonic ester R 1 X H 3 CO C O C C O OCH 3 R 1 R Dialkylated malonic ester
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Chemistry 342-2008 Mukund P. Sibi Reactions at the Alpha-Carbon of Carbonyl Compounds
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This note was uploaded on 01/23/2011 for the course CHEM 140B taught by Professor Nefzi during the Fall '06 term at UCSD.

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Reactions @ a-Carbon - Chemistry 342-2008 Mukund P. Sibi...

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