Charge-Directed Conjugate Addition Reactions in the Preparation of Substituted Methyl Ketones

Article abstract of DOI:10.1021/jo00146a025

Charge-directed conjugated addition reactions of the tert-butyl esters of α,β-unsaturated acylphosphoranes 2 have been used to prepare a variety of substituted methyl ketones.Substituted ylides 6 are prepared by alkylating ylide anions 4 generated by the addition of nucleophiles to 2 and are converted under acidic conditions to substituted (acylmethylene)phosphoranes 12 which are hydrolyzed to methyl ketones.The utility of these unsaturated acylphosphoranes as methyl vinyl ketone equivalents in conjugate addition-alkylation reactions is demonstrated in a synthesis of the racemic form of the sex pheromone of the California red scale, 14.