Enantioselective synthesis of 1,2,3-trisubstituted cyclopropanes using gem-dizinc reagents.

The first asymmetric cyclopropanation of allylic alcohols using gem-dizinc carbenoids, which allows the synthesis of 1,2,3-substituted cyclopropane derivatives in high yields and excellent enantio- and diastereoselectivities, is reported. The initially formed cyclopropylzinc undergoes an in situ B/Zn exchange with the stoichiometric chiral ligand to generate a cyclopropyl borinate that can be directly engaged in a Suzuki-Miyaura cross-coupling reaction.