Regio- and diastereoselective rearrangement of cyclopentane-1,3-diyl radical cations generated by electron transfer

Cyclopentane-1,3-diyl radical cations are readily available from azoalkanes or bicyclo[2.2.0]pentanes (housanes) by electron transfer. These short-lived intermediates may stabilize by numerous chemical processes, predominantly by 1,2-migration to form the corresponding cyclopentene derivatives after back electron transfer. This review focuses on the regio- and diastereoselectivities in the rearrangement of the strained cyclopentane-1,3-diyl radical cations and explores the mechanism of this novel 1,2-migration. This highly selective transformation offers attractive opportunities for the convenient and efficient synthesis of complex polycyclic structures.