Access to α,α-difluoro(arylthio)methyl oxetanes from α,α-difluoro(arylthio)methyl ketones and trimethylsulfoxonium halides: scope, mechanism and applications.

A general and practical method for the synthesis of α,α-difluoro(arylthio)methyl oxetanes that occurs by the reaction of α,α-difluoro(arylthio)methyl ketones with trimethylsulfoxonium halides is reported. This reaction proceeds via the sequential Corey-Chaykovsky epoxidation and regioselective ring-expansion pathways and features mild conditions, operational simplicity, gram-scalability, a broad substrate scope and high yields. α,α-Difluoro(arylthio)methyl oxiranes have been shown to be the reaction intermediates. The obtained α,α-difluoro(arylthio)methyl oxetanes were further converted into useful sulfone, butenolide, and tetrahydrofuran derivatives.