The reaction of aryldiazoacetates with enamines catalyzed by copper and rhodium complexes provided c-ketoesters in good yields. Careful analysis of the crude reaction mixture revealed a substituted enamine as the primary product, which was hydrolyzed over silica gel to give a c-ketoester as the final product. A reaction mechanism involving nucleophilic addition of an enamine to a metal carbene and subsequent hydrogen transfer was proposed.

Immobilized dirhodium (Ⅱ) catalysts having mixed chiral ligands enhance reactivity (AH) azetidinone) and influence stereoselectivity in cyclopropanation and carbon-hydrogen insertion reactions.

Diazo coupling reactions are capable of forming E,E,E-trienes from cinnamaldehydes in good yield. An efficient methodology is reported for the production of styryldiazomethanes that are subsequently used with catalysis for coupling and for cyclopropanation. A vast difference in product selectivity is seen with styryldiazomethane generated from the corresponding hydrazone via manganese dioxide oxidation and that formed in situ by treatment of the tosylhydrazone sodium salt of cinnamaldehyde with transition metal catalysts. This observation impacts understanding of the reaction mechanism for diazo decomposition.

The chiral dirhodium(Ⅱ) catalyst Rh2(MEAZ)4 increases diastereocontrol for intermolecular O-H insertion reactions of diazo esters having a chiral auxiliary over that achieved with Rh2(OAc)4.