催化学报

催化学报 ›› 2012, Vol. 33 ›› Issue (7): 1133-1138.DOI: 10.1016/S1872-2067(11)60394-X

• 研究论文 • 上一篇    下一篇

助剂对 L-脯氨酸催化直接不对称 Aldol 反应的影响

骆建轻1, 谭蓉1,a, 孔瑜1, 黎成勇1, 银董红1,2,b   

  1. 1湖南师范大学精细催化合成研究所, 湖南长沙 410081; 2湖南中烟工业有限责任公司技术研发中心, 湖南长沙 410014
  • 收稿日期:2012-02-19 修回日期:2012-04-09 出版日期:2012-06-21 发布日期:2012-06-21

Effect of Additives on L-Proline Catalyzed Direct Asymmetric Aldol Reactions

LUO Jianqing1, TAN Rong1,a, KONG Yu1, LI Chengyong1, YIN Donghong1,2,b   

  1. 1Institute of Fine Catalysis and Synthesis, Hunan Normal University, Changsha 410081, Hunan, China; 2Research and Development Center, China Tobacco Hunan Industrial Corporation, Changsha 410014, Hunan, China
  • Received:2012-02-19 Revised:2012-04-09 Online:2012-06-21 Published:2012-06-21

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817

被引次数

3

摘要： 在 L-脯氨酸催化的芳香醛与丙酮直接不对称 aldol 反应体系中添加二醇或二酚类助剂可有效提高反应活性. 助剂的使用降低了该反应体系中 L-脯氨酸的用量. 特别是以邻苯二酚为助剂时, 最佳反应条件下, 仅用 5 mol% L-脯氨酸与 1 mol% 助剂催化 2-硝基苯甲醛与丙酮直接不对称 aldol 反应, aldol 产物产率高达 90%, 对映选择性为 80%. 该反应产率比未加助剂条件下, L-脯氨酸用量为 30 mol% 时的反应产率高. 采用量子化学计算研究了助剂对该反应的促进作用. 结果表明, 助剂可与芳香醛的醛基形成氢键, 从而活化醛基, 提高反应效率. 邻苯二酚结构中相邻的羟基能与底物芳香醛羰基的氧原子形成双氢键, 大大活化了底物芳香醛的羰基. 因此, 该助剂可有效促进 L-脯氨酸催化剂的直接不对称 aldol 反应.

关键词: L-脯氨酸, 邻苯二酚, 芳香醛, 丙酮, 直接不对称 aldol 反应, 氢键作用

Abstract: The direct asymmetric aldol reaction of aromatic aldehydes with acetone catalyzed by L-proline was accelerated by the addition of diols or diphenols. The use of additives decrease the amount of L-proline needed and allowed the use of solvent free conditions. Catechol with two adjacent hydroxy groups on aromatic ring was the most efficient additive. Under the optimized conditions, 5 mol% L-proline with 1 mol% catechol gave excellent chiral selectivity (80% ee value) with > 90% yield, which was higher than that obtained using 30 mol% L-proline without an additive. Computations indicated that the additive promoted the reaction by an intermolecular hydrogen bond between the hydrogen of the hydroxyl group and the oxygen of the carbonyl group, which activated the carbonyl group of the aldehyde. Catechol with two adjacent hydroxyl groups on the aromatic ring can form two hydrogen bonds with the oxygen of the carbonyl group on the corresponding aldehyde. Therefore, the combination of L-proline and catechol was very efficient in catalyzing the direct asymmetric aldol reaction and gave a high yield in a short time.

Key words: L-proline, catechol, aromatic aldehyde, acetone, direct asymmetric aldol reaction, hydrogen bond interaction