1-Hydroxybenzotriazole → {(S)-2-[benzyloxylimino-methyl-pyrrolidine-1-yl]-1-cyclohexyl-2-oxo-ethyl}-carbamic acid tert-butyl ester

Participants

Reaction Steps

The solution of boc-L-α-cyclohexylglycine (1.27 g, 4.92 mmole), 1-hydroxylbenzotriazole (0.99 g, 7.38 mmole), diisopropylethylamine (2.54 g, 19.68 mmole), and O-benzotriazole-N,N,N,N-tetramethyl-urounium hexafluorophosphate (2.80 g, 7.38 mmole) in dichloromethane (30 ml) is stirred for 15 minutes at room temperature. A solution of pyrrolidine-2-carbaldehyde-O-benzyl-oxime (˜1.00 g, 0.49 mmole) in dichloromethane is added. The reaction solution is stirred for three hours at room temperature and then quenched with saturated NaHCO3 aqueous., extracted with dichloromethane. The organic layer is combined, dried, and concentrated under vacuum. The residue is purified by flash chromatography (silica gel; from 20% to 70% of ethyl acetate in hexane) to provide 1.81 g (83% over 2 steps) of the title compound. M+H+=444.2

Provenance & Evidence