Carbenoid versus Vinylogous Reactivity in Rhodium(II)-Stabilized Vinylcarbenoids

Rhodium(II)-stabilized vinylcarbenoid intermediates display electrophilic character at both the carbenoid site and the vinylogous position. The solvent and catalyst as well as the vinylcarbenoid structure have major effects on the regiochemical outcome of the reaction of vinylcarbenoids with alkenes and dienes. Reaction of vinylcarbenoids with vinyl ethers can lead to the formation of either cyclopropanes or cyclopentenes while reaction of vinylcarbenoids with cyclopentadiene can lead to the formation of either bicyclo[3.2.1]octadiene or bicyclo[2.2.1]heptene derivatives.