Participation by remote epoxy oxygen in the solvolysis of syn-6-oxabicyclo[3.1.0]hexan-3-ylmethyl p-bromobenzenesulphonate

Abstract

The kinetic data and products obtained from solvolysis of the syn- and anti-6-oxabicyclo[3.1.0]hexan-3-ylmethyl p-bromobenzenesulphonates (4a) and (5a) in aqueous ethanol demonstrate that solvolysis of (4a) probably involves participation of the epoxy oxygen to form the oxonium ion (7) which affords the rearranged products (6b) and (6c); however, such a participation is stereoelectronically prohibited in the anti-analogue (5a) and results mainly in the much slower formation of the unrearranged products (5b) and (5c).