Rhodium and ruthenium catalyzed enantioselective transfer hydrogenation of α,β-unsaturated carboxylic acids

ORGN 85

David M. Tellers, Claire Oakley, J. Chris McWilliams, and Yongkui Sun. Catalysis and Reaction Discovery and Development Lab (CRDD), Merck & Co., Inc, P.O. Box 2000, Rahway, NJ 07065-0900
The asymmetric hydrogenation of a,b-unsaturated carboxylic acids is a useful method for preparing chiral carboxylic acid derivatives. While there are a number of catalysts capable of performing this transformation using dihydrogen, relatively few examples of systems employing transfer hydrogenation techniques (e.g., formic acid, cyclohexadiene as reductants) have been reported. Given the success of ketone transfer hydrogenations and the utility of this methodology, we were interested in expanding the current scope of the chiral olefin transfer hydrogenation reactions. This paper describes our discovery and development of ruthenium and rhodium transfer hydrogenation catalysts and their application to the enantioselective reduction of unsaturated carboxylic acids (ee's up to 94%).

 

Asymmetric Reactions and Syntheses, Metal-Mediated Reactions, Materials, Molecular Recognition
8:00 PM-10:00 PM, Sunday, August 22, 2004 Pennsylvania Convention Center -- Hall D, Poster

Division of Organic Chemistry

The 228th ACS National Meeting, in Philadelphia, PA, August 22-26, 2004