Stereocontrolled addition of some sulphenyl halides to bicyclo[3.2.0]-hept-2-en-6-ones and modification of the adducts

Abstract

The bicycloheptenones (1) and (2) reacted with the sulphenyl chlorides (13)–(15) in a highly regioselective manner to give the corresponding adducts (3)–(8) in 77–92% yield. m-Chloroperoxybenzoic acid oxidation of the ketone (5) led to products (9), (10), (22), and (23) resulting from oxidation at sulphur and/or Bayer–Villiger ring expansion. The corresponding dichloroketone (8) suffers oxidation at sulphur only to give the sulphoxide (11) and the sulphone (12). The 7,7-dichlorobicyclohepten-6-one (8) yielded tetra-substituted cyclopentane derivatives (18)–(21) of defined stereochemistry on addition of methanol or piperidine across the C⁶–C⁷ bond.