苯乙酮酸薄荷醇酯的合成及其不对称Henry反应

Synthesis and Asymmetric Henry Reaction of Menthyl Phenylglyoxylate

在四乙氧基钛催化下,用丰产的天然薄荷醇为手性源与非手性苯乙酮酸乙酯进行酯交换得到含手性基团的苯乙酮酸薄荷醇酯,酯交换产率为68%;在引入手性基团的立体选择性控制下与硝基甲烷缩合,主要得到R-2-羟基-2-苯基-3-硝基丙酸薄荷醇酯,产率为86%,用IR、1HNMR、13CNMR、元素分析等确认了结构。用高效液相色谱分析了诱导不对称Henry缩合反应效果,其对映体过量e.e.值为52.8%。

In the presence of titanium （Ⅳ） ethoxide, chiral menthyl phenylglyoxylate was prepared via transesterification of ethyl phenylglyoxylate and the abundant natural chiral menthol, and the yield of the transesterification was 68%. In the auxiliaries of asymmetric factor, the menthyl R-2-hydroxy-2-phenyl-3- nitropropionate was synthesized by the Henry reaction with menthyl phenylglyoxylate and nitromethane, and the yield was 86%. Their structures were confirmed by IR, ^1H NMR, ^13C NMR spectroscopy and elemental analysis. The enantioselectivity was analyzed by HPLC, and the enantiomeric excess （e. e） was 52. 8%.