Triethylamine → tert-Butyl ((1R,3S)-3-isopropyl-3-[(4-phenyl-3,6-dihydropyridin-1(2H)-yl)carbonyl]-cyclopentyl}carbamate

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Reaction Steps

In a dried flask, (1S,3R)-3-[(tert-butoxycarbonyl)amino]-1-isopropyl-cyclopentanecarboxylic acid (200 mg, 0.7 mmol) and 4-phenyl-1,2,3,6-tetrahydropyridine (160 mg, 0.81 mmol) were suspended in methylene chloride (4 mL) under N2. Triethylamine (0.22 g, 2.2 mmol) was added followed by benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate (0.36 g, 0.81 mmol). The reaction was stirred overnight at room temperature and quenched by addition of saturated NaHCO3 solution. The resulting solution was extracted with methylene chloride three times. The combined extracts were dried (MgSO4), filtered and concentrated. Purification by flash chromatography on silica gel (gradient: 0-45% B over 15 min. Bottle A=hexanes, bottle B=EtOAc) to give 234 mg (80%) of desired product. MS calculated for C25H36N2O3: (M+H) 413; found 413.2.

Provenance & Evidence