Palladium-Catalyzed Oxidative Cross-Coupling of α-Cyanoketene Dithioacetals with Olefins

Efficient palladium-catalyzed cross-coupling reactions of the internal olefins alpha-cyanoketene dithioacetals with a variety of olefins were achieved in dioxane/HOAc/DMSO (9:3:1 v/v/v) under air atmosphere or by means of AgOAc as the terminal oxidant. Electron-deficient terminal olefins reacted to form the linear diene derivatives with air as the oxidant. Styrenes underwent the cross-coupling to give both the linear and branched dienes when using AgOAc as the oxidant. Unactivated cyclic and linear internal olefin substrates both reacted in the presence of a catalytic amount of benzoquinone in air to produce skipped dienes. The typical products were structurally confirmed by X-ray crystallography.