Triethylamine → Phenylmethyl N-[(5S)-5-[[(1,1-dimethylethoxy)carbonyl]amino]-6-oxohexyl]carbamate

Participants

Reaction Steps

A solution of sulfur trioxide pyridine complex (53.0 g, 333 mmol) in dimethylsulfoxide (300 mL) was added to a solution of benzyl (5S)-5-{[t-butyloxycarbonyl]amino}-6-hydroxyhexylcarbamate (8.64 g, 34.4 mmol) and triethylamine (14.4 mL, 103 mmol) in dichloromethane (130 mL) at 0° C. The cold bath was removed, and the reaction mixture was stirred for 23 h. It was then poured slowly into a mixture of ice and saturated aqueous sodium chloride (1000 mL). The resulting mixture was extracted with three 600 mL portions of ether. The ether extracts were then combined, washed with three 150 mL portions of saturated aqueous sodium chloride, and concentrated to 1200 mL. The concentrated ether phase was further washed with three 200 mL aliquots of 5% aqueous citric acid, and a 200 mL portion of saturated aqueous sodium chloride. After drying over magnesium sulfate, volatiles were removed under vacuum to afford (2S)-6-{[(benzyloxy)carbonyl]amino}-2-[(tert-butoxycarbonyl)amino]hexanal (37.58 g. 93%). 1H NMR (300 MHz, DMSO-d6) δ 9.44 (s, 1H), 7.46-7.23 (m, 6H), 5.02 (s, 2H), 3.85-3.75 (m, 1H), 3.07-2.93 (m, 2H), 1.77-1.60 (m, 1H), 1.56-1.23 (m, 5H), 1.41 (s, 9H).

Provenance & Evidence