Palladium-catalyzed oxidative C–O cross-coupling of ketene dithioacetals and carboxylic acids

Direct oxidative C–O cross-coupling reaction between active alkenes and carboxylic acids is presented. By utilizing Pd(OAc)2 as a catalyst and PhI(OAc)2 as an oxidant, ketene dithioacetals were smoothly acyloxylated in carboxylic acid–water solution, affording a variety of vinyl esters in a highly selective way with high efficiency and good functional group tolerance. A plausible mechanism is proposed that features a vinyl iodonium species as key intermediate.