Cobalt catalysed hydro-sulfenylation of Michael acceptors

Abstract

The reaction of certain types of Michael acceptors, limited to those having methylene groups, with a mixture of diphenyl disulfide and phenyl silane, under the influence of 10% of the cobalt catalyst, Co(eobe) 3, results in the formation of hydro-sulfenylated products, such as α-phenylthio carbonyl compounds, in moderate to good yields. The process involves intermediates having radical character, judging by the 5- exo-trig cyclisation product 21 observed in the reaction of α,β-unsaturated ester 20 having a suitable unsaturated side-chain.