COBALT-CATALYZED HYDRO-SULFENYLATION OF MICHAEL ACCEPTORS

The reaction of certain types of Michael accepters, limited to those h aving methylene groups, with a mixture of diphenyl disulfide and pheny l silane, under the influence of 10% of the cobalt catalyst, Co(eobe) 3, results in the formation of hydro-sulfenylated products, such as al pha-phenylthio carbonyl compounds, in moderate to good yields. The pro cess involves intermediates having radical character, judging by the 5 -exo-trig cyclisation product 21 observed in the reaction of alpha,bet a-unsaturated ester 20 having a suitable unsaturated sidechain. (C) 19 98 Elsevier Science Ltd. All rights reserved.