反应详情

N,N′-Dicyclohexylcarbodiimide (0.64 g, 3.1 mmol) and 4-(dimethylamino)pyridine (0.10 g, 0.1 mmol) was added to a stirred solution of compound 42 (1.23 g, 3.1 mmol) and compound 15 (0.83 g, 3.1 mmol) in dichloromethane. The reaction mixture was left stirring at room temperature for 72 h until completion of the reaction. Tile dicyclohexylurea formed was filtered off and the solvent removed in vacuo to yield a viscous colourless oil which was purified by column chromatography (ethyl acetate) on silica. The colourless material was then heated in ethanol and cooled to −60°, filtered off and dried in vacuo (P2O5). Yield 1.83 g (91%), [α]D=−22.35° at 24° C.

1. waitThe reaction mixture was left