Xiong Yan, Wang Fei, Huang Xiao, Wen Yuehong, Feng Xiaoming
Key Laboratory of Green Chemistry and Technology (Sichuan University), Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, China.
Chemistry. 2007;13(3):829-33. doi: 10.1002/chem.200601262.
A new chiral hydrogenated salen catalyst has been developed for the asymmetric Henry reaction which produces the expected products in moderate to high yields (up to 98 %) with excellent enantioselectivities (up to 96 % ee). A variety of aromatic, heteroaromatic, enal, and aliphatic aldehydes were found to be suitable substrates in the presence of hydrogenated salen 1 f (10 mol %), (CuOTf)(2)C(7)H(8) (5 mol %), and 4 A molecular sieves. This process is air-tolerant and easily manipulated with readily available reagents, and has been successfully extended to the synthesis of (S)-norphenylephrine in 67 % overall yield, starting from commercially available m-hydroxybenzaldehyde. Based on experimental investigations and MM+ calculations, a possible catalytic cycle including a transition state (8 or A) has been proposed to explain the origin of reactivity and asymmetric inductivity.
一种新型手性氢化萨伦催化剂已被开发用于不对称亨利反应，该反应能以中等到高的产率（高达98%）生成预期产物，对映选择性优异（高达96% ee）。发现在氢化萨伦1 f（10 mol%）、(CuOTf)₂C₇H₈（5 mol%）和4A分子筛存在下，多种芳香醛、杂芳香醛、烯醛和脂肪醛都是合适的底物。该过程对空气耐受，且用容易获得的试剂易于操作，并已成功扩展到从市售间羟基苯甲醛出发，以67%的总产率合成(S)-去甲肾上腺素。基于实验研究和MM+计算，提出了一个可能的催化循环，包括一个过渡态（8或A）来解释反应性和不对称诱导性的起源。
