Ary1(o-phenylaryl)thione S-Imides and S-Oxides Intramolecular Cyclization and Subsequent Rearrangment

Abstract

Aryl(o-phenylaryl)thione S-imides were formed by reaction of the corresponding thioketones with chloramine salts. The thione S-imides further underwent electrocyclization followed by the Stevens-type rearrangement involving intermediary cyclic sulfur ylides, to give Nphenyl sulfonyl- and N-tosy1-9-ary1-9-fluorenesulfenamides. The reaction of the thione containing a mesityl substituent gave E-isomers of thione S-imides stereoselectively. On the contrary, , both geometrical isomers of sulfines were obtained by oxidation of the thiones with m-chloroperbenzoic acid. E-isomers of the sulfines stereospecifically underwent electrocyclization followed by rearrangement in the presence of catalytic AlCl₃, whereas the Z-isomers were unreactive under these conditions. This reaction involved the Pummerer-type rearrangement of intermediary cyclic sulfoxides.