Preparing and Tuning the Reactivity of Palladium Carbenes and an Unusual Catalytic Isomerization of Diphenylcyclopropanes

Abstract

The preparation of palladium carbene intermediates from diphenylketene is proposed. Experiments to trap these intermediates with alkenes have been conducted and optimized, with cyclopropanes being prepared in up to 69% yield. This methodology has shown to be compatible with olefins, ethers, esters, anhydrides and various benzannulated norbornyl derivatives. In addition, an unusual palladium(II) catalyzed cyclopropane isomerization has been observed. Various substrates have undergone this isomerization affording two different olefin products in up to 61% yield. A catalytic cycle for this process is proposed.