Diisopropylethylamine → 2-[(1-Benzyloxycarbonylamino-2-methylpropyl)-methoxy-phosphinoyloxy]-5-tert-butoxycarbonylamino-pentanoic acid methyl ester

Participants

Reaction Steps

A solution of PyBOP (2.1 g, 4.0 mmol) in DMF (3 mL) was added to a mixture of (1-benzyloxycarbonylamino-2-methyl-propyl)-phosphonic acid monomethyl ester (1.0 g, 3.32 mmol) and 5-tert-butoxycarbonylamino-2-hydroxy-pentanoic acid methyl ester (865 mg, 3.5 mmol) in DMF (4 mL) under argon. DIPEA (2.28 mL, 13.3 mmol) was added dropwise and the mixture was stirred over night. Ethyl acetate was added and the mixture was washed with 10% KHSO4, satd. NaHCO3 and brine and dried. Concentration under reduced pressure followed by chromathography (heptane/EtOAc, 1:1→1:6) gave 2-[(1-benzyloxycarbonylamino-2-methyl-propyl)-methoxy-phosphinoyloxy]-5-tert-butoxycarbonylamino-pentanoic acid methyl ester (1.21 g, 69%).

Provenance & Evidence