A New Desulfurization Method: Application to the Synthesis of 11-Deoxyprostaglandin E2

Alkylation at carbon attached to sulfur of α-phenylthio or α-alkylthioketones, or reductive-alkylation of α-phenylthioketones provided a new regiospecific alkylation method of ketones.^1,2 In these procedures, desulfurization was effected either by reduction with lithium in liquid ammonia^1,2 or by use of Raney Ni-W-2.² Recently, buffered sodium amalgam method has been reported to be effective for desulfurization of β-ketosulfides as well as for desulfonylation of aryl alkyl sulfones.³ We wish to report here that desulfurization of α-phenylthioketones was achieved by treatment of the ketones with zinc and chlorotrimethylsilane. This observation would lead to a facile synthesis of α-substituted ketones.