Chiral dirhodium(II) carboxamidates are highly efficient catalysts for reactions between a variety of aldehydes and activated dienes. Catalyst loadings as low at 0.01 mol % have been realized with enantioselectivities up to 97%. Kinetic investigations reveal a pronounced electronic influence on the rate of the hetero-DielsAlder reaction with a Hammett value of ؉1.9 (versus ؉ ). Inhibition of the catalyst by reactant aldehyde is apparent, but reactions show first-order dependence on aldehyde and diene, and there is a variable dependence on catalyst.

The total synthesis of (S)-(+)-imperanene, a natural product found in Chinese medicine, has been completed in 12 steps from a commercially available cinnamic acid. The key step is highly enantioselective carbon-hydrogen insertion from a diazoacetate using a chiral dirhodium(II) carboxamidate catalyst. An elimination process essential to the construction has been optimized to avoid intramolecular Friedel-Crafts alkylation.

Chiral dirhodium(II) carboxamidates catalyze highly stereoselective hetero-Diels-Alder reactions of aromatic aldehydes with methyl-substituted Danishefsky's dienes with high turnover numbers. The methyl substituents of the diene influence both enantioselectivity in product formation and the rate of the reaction in the presence of chiral dirhodium(II) Lewis acids.

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