Reversal of Regioselectivity in Reactions of Donor-Acceptor Cyclopropanes with Eelectrophilic Olefins

Cyclopropanes bearing donor and acceptor groups at the opposite ends of the C-C bond should react with both nucleophiles and electrophiles. Their reactivity towards nucleophiles is well explored while only few specific electrophilic reagents give desired products.These methods are limited by the specific philicity of the carbon atoms resulting from the strong polarization of the central C-C bond. Herein, we report that vitamin B12 catalysis enables the transformation of initially electrophilic center into a nucleophilic radical that as such reacts with SOMOphiles. This radical-based strategy reverses the standard regioselectivity and thus complements the classical approaches.