Aryl sulfilimines

Treatment of vinyl or aryl sulfilimines (43) with dichloroketene was found to give y-thio-y-lactams (44), presumably by the sequence shown. For phenyl substituted sulfilimines, yields were found to be very low, presumably because of the stability of the phenyl ring, but N-tosylamidcs (45) were isolated as byproducts, which supports the proposed mechanism.41... 

P.B. Alper and co-workers developed a practical approach for the synthesis of 4,7-disubstituted indoles based on the Sommeiet-Hauser rearrangement of aryl sulfilimines. The multihundred-gram preparation of methyl 7-chloroindole-4-carboxylate was achieved. The synthesis commenced with the activation of a sulfide precursor with SOCI2 and coupling the intermediate with 3-amino-4-chlorobenzoate to afford an aromatic sulfilimine. This sulfilimine was exposed to excess triethylamine and heated to generate the sulfonium ylide that underwent the rearrangement. 

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