卤盐催化的α,β-环氧羧酸酯与异氰酸酯[3+2]环加成反应研究

Study of the Halide Salt Catalyzed[3+2]Cycloaddition ofα,β-Epoxy Carboxylate with Isocyanate

研究了一种α,β-环氧羧酸酯与异氰酸酯之间的[3+2]环加成反应.以溴化镁为催化剂,通过α,β-环氧羧酸酯与异氰酸酯发生[3+2]环加成反应,高效地合成出手性噁唑烷-2-酮.反应具有良好的底物适应性,对于手性环氧化合物参与的反应,产物对映体过量值保持良好.产物在碱性条件下开环,合成出紫杉醇C-13侧链((2R,3S)-3-苯甲酰胺-2-羟基3-苯基丙酸甲酯),光学纯度高达97%ee.

The[3+2]cycloaddition reaction ofα,β-epoxy carboxylate and isocyanate was investigated.By employing magnesium bromide as a catalyst,efficient synthesis of chiral oxazolidin-2-ones was achieved through aforementioned[3+2]cycloaddition reaction.The reaction exhibited good substrate adaptability.For reactions involving chiral epoxide compounds,the product enantiomeric excess remains good.Furthermore,under basic conditions,taxol C-13 side chain((2R,3S)-methyl 3-benzamido-2-hydroxy-3-phenylpropanoate)was synthesized via ring-opening reaction of the chiral oxazolidin-2-ones product with an optical purity of up to 97%ee.