Highly Diastereo‐ and Enantioselective Direct Aldol Reactions Promoted by Water‐Compatible Organocatalysts Bearing Central and Axial Chiral Elements
Highly Diastereo‐ and Enantioselective Direct Aldol Reactions Promoted by Water‐Compatible Organocatalysts Bearing Central and Axial Chiral Elements
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DOI：
10.1002/adsc.200800335
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发表时间：
2008-10
影响因子：
5.4
通讯作者：
Fangzhi Peng;Z. Shao;Xuewei Pu;Hongbin Zhang
中科院分区：
文献类型：
--
作者：
Fangzhi Peng;Z. Shao;Xuewei Pu;Hongbin Zhang
开发了两种新型双官能伯胺催化剂1(RA，S，S)和2(RA，R，R)，它们同时带有中心和轴向手性元素，用于在室温水存在下促进芳醛与环酮和无环酮的高非对映选择性和对映选择性的羟醛反应。催化剂2(RA，R，R)具有较高的反对映选择性(高达99：1)和对映体选择性(高达98%)，表明催化剂2的两个手性元素(RA，R，R)是匹配的，增强了立体化学控制。此外，催化剂2(RA，R，R)在室温下催化4-硝基苯甲醛与2-环己酮的直接Aldol反应，具有较高的反对映选择性(98：2)和对映体选择性(98%)。
Two novel bifunctional primary amine catalysts 1 (R A ,S,S) and 2 (R A ,R,R), which bear both central and axial chiral elements, have been developed to promote highly diastereoselective and enantioselective aldol reactions of arylaldehydes with cyclic and acyclic ketones in the presence of water at room temperature. The catalyst 2 (R A ,R,R) afforded the desired products with high levels of anti diastereoselectivity (up to 99:1) and enantioselectivity (up to 98%), showing that the two chiral elements of catalyst 2 (R A ,R,R) are matched, and enhance the stereochemical control. In addition, the catalyst 2 (R A ,R,R) was found to catalyze the direct aldol reaction of 4-nitrobenzaldehyde with 2-cyclohexanone under neat reaction conditions at room temperature with the high anti diastereoselectivity (98:2) and enantioselectivity (98%).