Nucleophilic benzoylation using lithiated methyl mandelate as a synthetic equivalent of the benzoyl carbanion. Oxidative decarboxylation of alpha-hydroxyacids

The synthesis of alkyl aryl ketones using lithiated methyl mandelate as a s ynthetic equivalent of the benzoyl carbanion is reported (Umpolung). The me thodology involves alkylation of methyl mandelate, hydrolysis of the ester group and oxidative decarboxylation of the resulting -alpha -hydroxyacids. The last step is carried out in a catalytic aerobic way using a Co(III) com plex in the presence of pivalaldehyde under very mild and advantageous cond itions. The procedure is also applied to methyl mandelates substituted on t he aromatic ring. (C) 2001 Elsevier Science Ltd. All rights reserved.