Diphenylphosphinoyl-mediated synthesis of ketones.

alpha-Diphenylphosphinoyl ketones are selectively and sequentially alkylated at the alpha-position. Double lithiation and selective alkylation occurs at the less stabilised gamma-position. Dephosphinoylation of the alkylation products gives ketones. Mono-alkylation is selective, highly crystalline intermediates are formed and a one-pot strategy is possible. The method is ideally suited for the preparation of acid-sensitive ketones.