Pyridine → 2-(1,1-Dimethylethyl) 1-(phenylmethyl) (2S)-1,2-pyrrolidinedicarboxylate

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Reaction Steps

126.9 (1 mol) of oxalyl chloride is added dropwise over 15 minutes to a stirred mixture of 200 ml absolute dimethylformamide and 500 ml absolute acetonitrile cooled to -20°. The solution is stirred for a further 15 minutes at -20° and then 249 g (1 mol) N-carbobenzoxy-L-proline is added. After 15 minutes of stirring, the mixture is treated dropwise with a mixture of 250 ml of absolute tert.-butanol and 200 ml absolute pyridine at such a rate that the temperature of the mixture does not rise above -15°. Cooling of the mixture is then stopped, and the mixture is maintained at room temperature for 3 hours. The mixture is worked up by partitioning between 2N sodium carbonate solution and methylene chloride and obtaining the heading compound from the methylene chloride phase as an oil nD23 = 1.5015 which slowly crystallizes out.

Provenance & Evidence