Generation of Iminyl Radicals through Sulfanyl Radical Addition to Vinyl Azides

Benzenethiol and 2-benzo[ b ]thiophenethiol undergo almost instantaneous reaction with α-azidostyrene and 1-azido- trans -stilbene in benzene, at room temperature, to give corresponding β-sulfanylated imines and enamines in virtually quantitative yield. With α-azidostyrene, phenethyl and allyl mercaptan are found to react in a similar fashion, but to rates very much lower. Results are interpreted in terms of radical-chain reactions involving intermediacy of 2-sulfanyliminyl radicals which could result from sulfanyl radical attack at the azide β-carbon followed by nitrogen extrusion by the ensuing radical adduct.