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.