Cobalt-Catalyzed Asymmetric Cyclopropanation of Electron-Deficient Olefins

The cobalt(II) complex of a D 2 -symmetric chiral porphyrin [Co( 1 )] is an effective catalyst for asymmetric cyclopropanation of electron-deficient olefins, including α,β-unsaturated esters, amides, ketones, and nitriles. Due to the absence of dimerization of diazo compounds, the catalytic reactions can be performed in one-pot protocol using olefins as the limiting reagent, forming the desired electrophilic cyclopropane derivatives in high yields and selectivities under mild conditions. In most cases, both excellent diastereo- and enantioselectivity were achieved.