N-ARYL-ETHENESULPHENAMIDES; THERMAL TRANSFORMATION OF TWO N-(1-NAPHTHYL)-ETHENESULPHENAMIDES INTO 1H-BENZINDOLES

Article abstract of DOI:10.1016/S0040-4020(01)90025-0

Reaction of vinylmagnesium bromide with morpholine or piperidine-N-sulphenyl chlorides 3a,b affords the N-ethenylthio-morpholine and -piperidine 4a,b.When treated with stoichiometric amounts of an arylamine and methanesulphonic (or trifluoroacetic) acid, the sulphenamides 4 are converted into N-aryl-ethenesulphenamides 6a-e.On heating in toluene, two of these sulphenamides 6d and 6e undergo <3.3>-sigmatropic rearrangements followed by cyclisation of the intermediate amino-thioaldehydes yielding the corresponding 1H-benzindoles 8a,b.