Cyclopentadienyl 3,5-dimethoxybenzyl nitrosyl triphenylphosphine rhenium

Water-soluble (l,5-cyclooctadiene)[(3i ,4i )-3,4-bis(diphenyl-phosphino)-1,1 -dimethylpyrrolidiniumjrhodium bis(tetrafluo- 

Catalyst (2) Dehydro amino acid (3) Substrate catalyst Temp. (°C) ee (%) 

A silica-supported rhodium complex of (3f ,4f )-3,4-bis(diphenylphosphino)pyrrolidine (5) is also an effective catalyst. This heterogeneous catalyst mediates asymmetric hydrogenation of (3a) as well as its methyl ester in comparable selectivities to the homogeneous one shown above. 

(a) Thkaya, H. Noyori, R. Comprehensive Organic Synthesis 1991, 8, Chapter 3.2. (b) Noyori, R. Kitamura, M., In Modem Synthetic Methods Sheffold, R. Ed. Springer Berlin, 1989 Vol. 5, p 115. 

Kinzel, E. Chem. Commun./J. Chem. Soc., Chem. Commun. 1986,1098. 

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