Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331, USA.
J Org Chem. 2010 Nov 5;75(21):7279-90. doi: 10.1021/jo1015008.
A highly enantio- and diastereoselective anti-aldol process (up to >99% ee, >99:1 dr) catalyzed by a proline mimetic-N-(p-dodecylphenylsulfonyl)-2-pyrrolidinecarboxamide-has been developed. Catalyst loading as low as 2 mol % can be employed. Use of industry-friendly solvents for this transformation as well as neat reaction conditions have been demonstrated. The scope of this transformation on a range of aldehydes and ketones is explored. Density functional theory computations reveal that the origins of enhanced diastereoselectivity are due to the presence of nonclassical hydrogen bonds between the sulfonamide, the electrophile, and the catalyst enamine that favor the major anti-Re aldol TS in the Houk-List model.
一种由脯氨酸类似物-N-（对-十二烷基苯磺酰基）-2-吡咯烷甲酰胺催化的高度对映选择性和非对映选择性的反羟醛缩合反应（高达>99%ee，>99:1dr）已经被开发出来。该反应仅需 2mol%的催化剂用量。该转化使用了工业友好型溶剂，反应条件也很温和。还探索了该转化在一系列醛和酮上的范围。密度泛函理论计算表明，增强的非对映选择性的起源是由于磺酰胺、亲电试剂和催化剂烯胺之间存在非经典氢键，这有利于 Houk-List 模型中主要的反-Re 羟醛缩合过渡态。
