Optically active aldiminato cobalt(II) complexes as efficient catalysts for enantioselective cyclopropanation of styrenes with diazoacetates

The optically active cobalt(II) complex, MPAC, has proved to be efficient enantioselective catalyst for the cyclopropanation of styrenes with diazoacetates. The addition of a catalytic amount of N-methylimidazole remarkably accelerated the cyclopropanation reaction to improve both the chemical and optical yields of the product.