高效体烯效唑的不对称还原合成方法

Asymmetric Reduction Synthetic Method of Preparing High-Efficiency Uniconazole

本文以L-脯氨酸为起始原料,合成了α-二取代吡咯烷-2-甲醇盐酸盐,并研究了其作为手性助剂在硼氢化钠还原烯效唑的不对称反应中的应用。为进一步提高产率,考察了反应温度、手性助剂用量及溶剂和催化剂种类对ee值的影响。结果表明,硼氢化钠还原烯效唑最优条件是:50℃下,用1.5当量的手性助剂,二氯乙烷作溶剂,氯化锌为催化剂。在此条件下,能以较高的立体选择性和化学选择性得到相应的烯效唑。

Disubstituted pyrrolidine-2-methanols were synthesized starting from L-proline and their application as chiral auxiliary in the asymmetric NaBH;reduction of uniconazole was investigated.In order to further improve the ee value,a series of experiments were conducted to examine effect of the reaction temperature,the amount of L-proline hydrochloride derivative used,the type of solvent and the type of catalyst.As a result,the optimum conditions for the chemical reaction are:using NaBH;at 50℃with 1.5 equivalents of chiral auxiliary 4,dichloroethane as solvent,zinc chloride as catalyst.Under this condition,uniconazole were obtained in good chemical yields with high ee values(up to 71%).