Stereospecific Pd-Catalyzed Intermolecular C(sp(3))-C(sp) Cross-Coupling of Diarylmethyl Carbonates and Terminal Alkynes Under Base-Free Conditions.

A palladium-catalyzed intermolecular decarboxylative C(sp(3))-C(sp) coupling of diarylmethyl carbonates and terminal alkynes has been developed. The reaction proceeds smoothly under external base-free conditions to deliver the corresponding alkynylated diarylmethanes with the liberation of CO2 and MeOH as the sole byproducts. Moreover, enantioenriched diarylmethyl carbonates are stereospecifically converted to optically active cross-coupling products with inversion of configuration. Thus, the stereospecific palladium catalysis can provide new and unique access to the alkynylated chiral tertiary stereocenters, which are relatively difficult to construct by conventional methods.