A general and efficient cobalt(II)-based catalytic system for highly stereoselective cyclopropanation of alkenes with [alpha]-cyanodiazoacetates

The utility of [Co(P1)], the cobalt(II) complex of the [D.sub.2]-symmetric chiral porphyrin 3,5-[Di.sup.t]Bu-ChenPhyrin, as an effective catalyst for catalyzing asymmetric olefin cyclopropanation with the acceptor/acceptor-type diazo reagent [alpha]-cyanodiazoacetates is described. The Co(II)-based catalytic system could be operated in a one-time protocol under mild conditions to yield the desired cyclopropane products in high yields with both high diastereo- and enantioselectivity.