Ru(II)-Catalyzed Deoxygenative Formal [3 + 1 + 2] Benzannulation of Allyl Alcohols and Acetylenediesters via C-H Activation and Selective Carbon-Carbon Triple Bond Cleavage.

An unprecedented Ru(II)-catalyzed deoxygenative, site-selective formal [3 + 1 + 2] benzannulation reaction for the efficient synthesis of highly substituted benzene molecules is reported. This reaction between allyl alcohols and acetylenedicarboxylate esters proceeds via cascade C-H activation, consecutive double migratory insertion with alkynes, and cycloaromatization followed by an unusual specific C-C triple bond cleavage.