K2S2O8-mediated regio- and stereo-selective thiocyanation of enamides with NH4SCN

A direct and straightforward thiocyanation of enamides with NH4SCN under metal-free conditions has been accomplished. A variety of (E)-β-thiocyanoenamides are readily produced in a regio- and stereoselective manner. The protocol features mild reaction conditions, good functional group tolerance and operational simplicity. The potential utility of this strategy was further demonstrated by transformation of thiocyanate into thiotetrazole-containing compounds and a Pd-catalyzed cross-coupling reaction to afford six- or seven-membered sulfur-containing heterocycles. Mechanistic insights into the reaction indicate that the reaction may proceed via a radical mechanism