FACTORS INFLUENCING NATURE OF EPISULFONIUM ION IN SULFENYL CHLORIDE ADDITION TO TERMINAL OLEFINS

Methane- and benzenesulfenyl chloride afforded predominantly anti-Markovnikov oriented adducts with terminal alkyl substituted olefins and vinyl chloride. This adduct selectivity increased with increasing bulkiness of the alkyl substituent of the substrate. These kinetically controlled adducts were found to readily undergo acid-catalyzed isomerization to the thermodynamically more stable Markovnikov adducts. Phenyl substituents on the olefin caused Markovnikov orientation of the kinetically controlled adducts. Exclusive trans-stereospecific addition to norbornene and acenaphthylene was established. The mechanism of such additions and, in particular, the factors influencing the transition state, i.e., the ring opening of the episulfonium ion intermediate, are discussed. © 1968, American Chemical Society. All rights reserved.