Neighbouring-group participation by sulphinyl-oxygen. Part II. A Walden cycle at a sulphur atom

Abstract

Conversion of syn- and anti-3-endo-phenylsulphinylbicyclo[2,2,1]hept-5-ene-2-endo-carboxylic acids and esters into anti- and syn-iodohydrins, respectively, with inversion of configuration of the sulphinyl-group, and then conversion of the iodohydrins into the anti- and syn-bicycloheptene sulphoxides constitutes a Walden cycle at the sulphur atom. The inversion which accompanies the formation of iodohydrins is caused by intramolecular nucleophilic attack by sulphinyl-oxygen on the norbornene double bond, and hydrolysis of the intermediate O-alkylsulphoxonium salts. A new, selective method of converting iodohydrins into alkenes is described.