Qin Bo, Xiao Xiao, Liu Xiaohua, Huang Jinglun, Wen Yuehong, Feng Xiaoming
Key Laboratory of Green Chemistry & Technology (Sichuan University), Ministry of Education, College of Chemistry, Sichuan University, Chengdu, China.
J Org Chem. 2007 Nov 23;72(24):9323-8. doi: 10.1021/jo701898r. Epub 2007 Nov 1.
A new chiral N,N'-dioxide-Cu(I) catalyst has been developed for the asymmetric Henry (nitroaldol) reaction. The approach benefited from the easy modification of the chiral space. As the highly effective N-oxide ligand, 1d has been adopted for the Henry reaction with both aromatic and heteroaromatic aldehydes. The corresponding nitro-alcohol products were obtained in good yields with high enantiomeric excesses up to 98%. Moreover, alpha-ketoesters were also catalyzed by this catalyst to give attractive optically active alpha-hydroxy beta-nitro esters containing chiral quaternary carbon centers (up to 99% ee). On the basis of a combination of several techniques including the 1H NMR, ESI-HRMS, and MM2 calculations, the proposed mechanism was presented to explain the origin of reactivity and asymmetric inductivity.
一种新型手性N,N'-二氧化物-Cu(I)催化剂已被开发用于不对称亨利（硝基醇）反应。该方法得益于对手性空间的轻松修饰。作为高效的N-氧化物配体，1d已被用于与芳香醛和杂芳醛的亨利反应。相应的硝基醇产物以良好的产率和高达98%的高对映体过量获得。此外，该催化剂还能催化α-酮酯生成具有吸引力的含手性季碳中心的光学活性α-羟基-β-硝基酯（对映体过量高达99%）。基于包括1H NMR、ESI-HRMS和MM2计算在内的多种技术的结合，提出了反应机理以解释反应活性和不对称诱导性的起源。
