Rearrangement of some allylic sulphinate esters to allylic sulphones. Ion-pair and sigmatropic shift mechanisms

Abstract

The mechanism of rearrangement of a number of allylic sulphinate esters to the corresponding allylic sulphones on heating in formamide has been investigated as a function of substrate structure. Simple systems such as crotyl and α-methylallyl sulphinate appear to follow a [2,3]-sigmatropic shift pathway, while others, particularly cyclohex-2-enyl sulphinates, show the characteristics of an ion-pair mechanism.