Theoretical Studies on Diastereo‐ and Enantioselective Rhodium‐Catalyzed Cyclization of Diazo Compound via Intramolecular CH Bond Insertion

Theoretical studies on the stereoselectivity of the dirhodium tetracarboxylate (carboxamidate)-catalyzed intramolecular CH insertion reaction, which gives a variety of carbo- or heterocyclic compounds, have been performed by the following procedure. First, the CH insertion mechanism of simple systems was studied by the hybrid density functional theory (B3LYP) calculations. On the basis of these B3LYP structures, stereoselectivities of the reactions of realistic substrates were examined by the PM3 calculations with some structural constraints. The origin of the diastereo- and enantioselectivities in the four- and five-membered ring formation reactions with an achiral or a chiral Rh catalyst has thus been elucidated.