Catalyst-free photocyclopropanation of dibromomalonates with alkenes: an approach to multisubstituted cyclopropanes

We report herein a novel photocyclopropanation of dibromomalonates with alkenes in the presence of Hünig base. This protocol provides an environmentally benign approach for the synthesis of multisubstituted cyclopropanes, since no catalyst is required. The Photo-induced Electron Transfer (PET) from Hünig base to dibromomalonate is the key process during this transformation.