Photochemistry of Imine-Group VI Carbene Complexes with Alkenes: Synthetic Scope and Photochemical Aspects

The irradiation of imine-group VI carbene complexes with alkenes leads to the formation of 1-pyrrolines through a mechanism involving an initial cyclopropanation followed by a light-induced [1,3]-sigmatropic rearrangement. The reaction has no limitations on the structural nature of the imine-carbene complexes and is general for terminal and acyclic or cyclic 1,2-disubstituted electron-poor olefins. From the studies on photochemical aspects such as excited-state quenching, quantum yield, excited-state sensitizers and Stern-Volmer plots, it is concluded that both excited states, singlet and triplet, undergo the photoreaction. As far as we know, this is the first photochemical study on these kinds of compounds