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 stereo-selective 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 the thiocyanate into thiotetrazole-containing compounds and Pd-catalyzed cross-coupling reaction to afford six- or seven-membered sulfur-containing heterocycles. Mechanistic insights into the reaction indicates that the reaction proceeded via radical mechanism.