Configurational Stability and Reactions of Benzylic Carbanions with an Acyloxy or Dialkylphosphoryloxy Substituent
Secondary and tertiary α-methylbenzyllithium compounds were prepared by deprotonation of the corresponding carbon acids. Carbanions with a 2,4,6-triisopropylbenzoyloxy substitutent are configurationally stable in toluene/20% diethyl ether and react with electrophiles with retention (protonation, acylation with methyl chloroformate and dimethyl carbonate) or inversion (trimethyltin chloride). Secondary and tertiary carbanions with a dialkylphosphoryloxy substituent isomerise as soon as they are formed to α-hydroxyphenyl-methylphosphonates with retention of configuration (phosphate-phosphonate rearrangement).
KeywordsCarbon Acid Enantiomeric Excess Configurational Stability Dimethyl Carbonate Hydroxy Ketone
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