Amplification of Asymmetric Induction in Sequential Reactions of Bis-diazoacetates Catalyzed by Chiral Dirhodium(II) Carboxamidates

Two sequential intramolecular carbon−hydrogen insertion or cyclopropanation reactions of bis-diazoacetates using chiral dirhodium(II) carboxamidate catalysts are reported. The initial metal carbene transformation forms an excess of one enantiomer that with the second transformation further enhances stereocontrol (kinetic amplification). Diastereoselectivity and enantioselectivity for product formation are controlled by the catalyst.