Pd-catalyzed enantioselective synthesis of uncommon inherently chiral tribenzoannulenes

In this issue of Chem Catalysis, Zhu and co-workers describe the Pd-catalyzed enantioselective synthesis of inherently chiral 9-benzylidene-9H-tribenzo[a,c,e][7]annulene derivatives via olefination of tribenzocycloheptatrienone N-sulfonylhydrazone with benzyl bromides. They applied the reaction to prepare the first inherently chiral monophosphine ligand. Density functional theory (DFT) calculations pinpoint the β-hydride elimination as the enantioselectivity-determining step.