Usage of the carboxylate leaving group in transition-metal-catalyzed cross-coupling and related reactions

This account describes our recent work on catalytic cross-coupling reactions using carboxylate and carbonate leaving groups in the electrophilic substrate. Some bisphosphine-chelated palladium(O) complexes are effective for the cleavage of benzylic C-O bonds in benzyl carbonates and acetates. This C-O bond cleavage was utilized in catalytic reactions of these benzylic esters; the nucleophilic benzylic substitutions and the crosscoupling reactions with organometallic compounds. Furthermore, vinyl acetate was proved to work as the coupling partner of arylboronates in the presence of [RhCl(cod)] ₂-DPPB. Interestingly, the organoborons react selectively at the position β to the leaving group in the alkenyl ester when the rhodium-catalyzed reaction is conducted in the absence of the bisphosphine.