(R)-5-Biphenyl-4-ylmethyl-3-methylene-2-oxo-pyrrolidine-1-carboxylic acid tert-butylester → (3R,5S)-5-biphenyl-4-ylmethyl-3-methyl-2-oxo-pyrrolidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

Ethanol (1 ml) is added to a mixture of 100 mg (R)-5-biphenyl-4-ylmethyl-3-methylene-2-oxo-pyrrolidine-1-carboxylic acid tert-butyl ester (4-a, R1=Boc) and 10% palladium on carbon (10 mg, 50% water wet, Degussa type E101 NE/W). Hydrogen gas is applied to the mixture. The mixture is stirred at ambient temperature and pressure for 24 h. The mixture is then filtered over Celites and washed with ethanol (2×0.5 ml). The mixture is then concentrated in vacuo to give (3R,5S)-5-biphenyl-4-ylmethyl-3-methyl-2-oxo-pyrrolidine-1-carboxylic acid tert-butyl ester (3-a, R1=Boc) and (3S,5S)-5-biphenyl-4-ylmethyl-3-methyl-2-oxo-pyrrolidine-1-carboxylic acid tert-butyl ester (3-b, R1=Boc). Diastereomer ratio 20:80 (3-a, R1=Boc: 3-b, R1=Boc) as determined by hplc. Spectroscopic data in described in WO/2008/083967, for example, Examples 14 and 18.

Provenance & Evidence