Palladium-Catalyzed Arylcarboxylation of Propargylic Alcohols with CO2 and Aryl Halides: Access to Functionalized α-Alkylidene Cyclic Carbonates.

A palladium-catalyzed, three-component reaction between propargylic alcohols, CO2, and aryl halides was developed whereby a sequential carboxylation, trans-oxopalladation of the C≡C bond by an ArPdX species, and a reductive elimination procedure afforded a series of functionalized α-alkylidene cyclic carbonates in moderate to excellent yields. Notably, the configuration of these tetrasubstituted olefins was dominated by the trans-oxopalladation step where the aryl group derived from ArX is located trans to the oxygen attached in the double bond. This protocol features simultaneous formation of four novel bonds in a one-pot reaction, representing an efficient method for incorporation of CO2 into heterocycles.