Sigmatropic rearrangements of unsaturated dixanthogens

Abstract

Diallyldixanthogen and di(but-2-enyl)dixanthogen are unstable compounds, and decompose by two [3,3] sigmatropic rearrangements to the corresponding disulfides and carbon oxysulfide. Intermediates in the rearrangements are detected by infrared and ¹H n.m.r. techniques. A minor contribution from a four-centre mechanism is demonstrated. The stability of di(pent-4-enyl)-dixanthogen supports the suggested mechanism for the rearrangements.