(E)-(R)-4-tert-butoxycarbonylamino-5-(3'-chloro-biphenyl-4-yl)-2-methyl-pent-2-enoic acid ethyl ester → (S)-4-tert-butoxycarbonylamino-5-(3'-chloro-biphenyl-4-yl)-2-methyl-pentanoic acid ethyl ester

Participants

Reaction Steps

Next, to a solution of (E)-(R)-4-tert-butoxycarbonylamino-5-(3′-chloro-biphenyl-4-yl)-2-methyl-pent-2-enoic acid ethyl ester (2.5 g, 5.63 mmol) in ethanol (20 mL) is added PUC (250 mg) and the mixture is stirred overnight under an atmosphere of hydrogen (H2 balloon). The catalyst is filtered through a Celite pad and, the filtrate is concentrated to give (S)-4-tert-butoxycarbonylamino-5-(3′-chloro-biphenyl-4-yl)-2-methyl-pentanoic acid ethyl ester.

Provenance & Evidence