Catalytic Generation of <i>o</i>-Quinone Dimethides by a Nondiazo Approach via Donor/Donor Platinum Carbenes

A platinum-catalyzed reaction of enynones with various dienophiles has been developed for the construction of tetrahydronaphthalene derivatives, which undergo a Diels-Alder reaction process with platinum carbenes and <i>o</i>-quinone dimethide (<i>o-</i>QDM) intermediates. In this protocol, an alkoxy-substituted conjugated enynone is used as a nondiazo carbene precursor for the generation of <i>o-</i>QDMs, thereby extending the methods available for the generation of <i>o-</i>QDMs. The reaction is characterized by its high atom economy, high diastereoselectivity, and broad substrate scope.