Scope and limitations of the [1,2]-alkylsulfanyl (SMe, SEt and SCH2Ph) andsulfanyl (SH) migration in the stereospecific synthesis of substituted tetrahydrofurans

Acid catalysed rearrangement of a series of 4-RS-1,3-diols (R = Me, Et, Bn and H) with toluene-p-sulfonic acid in dichloromethane gives stereospecific ally substituted tetrahydrofurans via a [1,2]-SR shift in near quantitative yield. We comment on the structural variation of the migrating (RS) substi tuent and that of the migration origin and terminus on the outcome of the t itle reaction. We also report on the surprising similarity between an alkyl sulfanyl (RS) and sulfanyl (SH) migrating group.