benzyloxycarbonyl-L-valyl-L-proline t-butyl ester → tert-butyl (2S)-1-[(2S)-2-amino-3-methylbutanoyl]pyrrolidine-2-carboxylate

Participants

Reaction Steps

N-[(Phenylmethoxy)carbonyl]-L-valyl-L-proline tert-butyl ester (905 g) was dissolved in ethanol (4 liters) and 10% palladium on carbon (20 g) was added. The reaction mixture was shaken under a hydrogen atmosphere (50 psi) for 12 hours and then the catalyst was removed by filtration through through diatomaceous earth. The filtrate was concentrated under vacuum and the residue twice re-evaporated from toluene (1 liter) to give L-Valyl-L-Proline tert-butyl ester as an oil (628 g); TLC, Rf =0.2, acetone:hexane (20:80); MS: m/z=271(M+1).

Provenance & Evidence