Xh. Wang et al., [2,3]-SIGMATROPIC REARRANGEMENT OF BETA-PHENYLSULFONYL PROPARGYLIC SULFENATES AS A METHOD FOR PREPARING 1,4-BIS(PHENYLSULFONYL)-1,3-BUTADIENES, Journal of organic chemistry, 58(20), 1993, pp. 5377-5385
Several beta-sulfoxy-substituted acetylenic carbinols were prepared by
the addition of thiyl radicals and oxygen to conjugated enynes. The p
roducts obtained are derived from thiyl radical attack at the olefinic
bond to generate a propargylic radical. Capture of this radical by ox
ygen followed by hydrogen transfer from thiophenol gives a hydroperoxi
de intermediate, which undergoes oxygen transfer by both intra- and in
termolecular pathways. The resultant beta-phenylsulfinyl propargylic a
lcohols proved to be versatile intermediates for the preparation of se
veral different classes of compounds. The [2,3]-sigmatropic sulfinate
to sulfoxide rearrangement was found to give 1,4-bis(phenylsulfonyl)-1
,3-butadienes, alpha,beta-unsaturated phenylsulfoxy ketones, and beta-
phenylsulfonyl alpha-allenic sulfoxides' Oxidation of the sulfoxy moie
ty to the sulfone followed by sulfinate formation with phenylsulfenyl
chloride produces, after [2,3]-sigmatropic rearrangement, beta-phenyls
ulfonyl alpha-allenic sulfoxides. In certain cases these allenes could
be isolated, but were usually isomerized in situ and further oxidized
to give 1,4-bis(phenylsulfonyl)-1,3-butadienes. The [2,3]-sigmatropic
rearrangement of beta-phenyl-sulfinyl-substituted propargylic alcohol
s proceeds by an entirely different course. With these systems, a doub
le sigmatropic process occurs leading to the formation of vinyl sulfin
ates which are readily hydrolyzed to give alpha,beta-unsaturated pheny
lsulfoxy ketones.