Stereoselective synthesis of cyclobutyl γ-amino acids leading to branched peptides with a cyclobutane core

Aryl-Radical-Initiated Z-Olefin Synthesis via Synergistic Palladium and Photocatalysis

We report a novel photocatalyzed selective functionalization of terminal olefins for the synthesis of Z-olefins and cyclobutanes under mild conditions in excellent yields. A series of Z-cinnamic acid derivatives, enamines, and amide-containing cyclobutanes were efficiently synthesized using this method. Mechanistic studies indicated that the success of this reaction is based on the triple radical relay strategy, anion-π interaction for aryl halide activation and aryl radical generation, palladium for controlling chemoselectivity of the aryl radical, and photocatalyst for controlling stereoselectivity via diradical species, respectively.