Facile regio- and stereo-specific allylic oxidation of gem-dimethyl olefins via addition of benzenesulphenyl chloride. Synthesis of allylic oxygenated terpenes

Abstract
Novel and facile terminal trans-allylic and internal allylic oxidations of the gem-dimethyl olefin terminus of the terpenoids (1) are described which take place site-, regio-, and stereo-specificially via the same intermediate adduct between benzenesulphenyl chloride and (1). By this method, the allylic oxygenated terpenes (±)-nuciferal (11), (±)-ar-turmerone (12), (±)-ipsdienol (3c), neotorreyol (2e), (±)-6-hydroxydendrolasin (3e), and 6-oxodendrolasin (14) were synthesized.