Benzyl Alcohol → ethyl (1R,3S)-3-benzyloxycarbonylaminocyclohexanecarboxylate

Participants

Reaction Conditions

Reaction Steps

(1S,3R)-3-(Ethoxycarbonyl)cyclohexanecarboxylic acid, 18a, (10.0 g, 49.9 mmol) was dissolved in toluene (100 mL) and treated with triethylamine (7.6 mL, 54.9 mmol) and DPPA (12.2 mL, 54.9 mmol). The resulting solution was heated to 110° C. and stirred for 1 hour. After cooling to 70° C., benzyl alcohol (7.7 mL, 74.9 mmol) was added, and the mixture was heated to 85° C. overnight. The resulting solution was cooled to room temperature, poured into EtOAc (150 mL) and water (150 mL) and the layers were separated. The aqueous layer was extracted with EtOAc (2×75 mL) and the combined organic extracts were washed with water (100 mL) and brine (100 mL), dried over Na2SO4 and concentrated in vacuo. The crude material was purified by silica gel chromatography (0%-50% EtOAc/hexanes) to provide 18b (15.3 g, containing ˜25% benzyl alcohol), which was used for the next step without further purification.

Provenance & Evidence