Guan Yong, López-Alberca Maria P, Lu Zhenjie, Zhang Yu, Desai Aman A, Patwardhan Aniruddha P, Dai Yijing, Vetticatt Mathew J, Wulff William D
Department of Chemistry, Michigan State University, East Lansing, MI 48824 (USA), Fax: (001) 517-3353-1793 http://www2.chemistry.msu.edu/faculty/wulff/myweb26/index.htm.
Chemistry. 2014 Oct 20;20(43):13894-900. doi: 10.1002/chem.201404587. Epub 2014 Sep 9.
Alkynyl aziridines can be obtained from the catalytic asymmetric aziridination (AZ reaction) of alkynyl imines with diazo compounds in high yields and high asymmetric inductions mediated by a chiral boroxinate or BOROX catalyst. In contrast to the AZ reaction with aryl- and alkyl-substituted imines, alkynyl imines react to give cis-substituted aziridines with both diazo esters and diazo acetamides. Remarkably, however, the two diazo compounds give different enantiomers of the cis-aziridine from the same enantiomer of the catalyst. Theoretical considerations of the possible transition states for the enantiogenic step reveal that the switch in enantiomers results from a switch from Si-face to Re-face addition to the imine, which in turn is related to a switch from reaction with an E-imine in the former and a Z-isomer of the imine in the latter.
炔基氮杂环丙烷可以通过手性硼酸酯或硼氧烷催化剂介导的炔基亚胺与重氮化合物的催化不对称氮杂环丙烷化反应（AZ反应）以高收率和高不对称诱导得到。与芳基和烷基取代亚胺的AZ反应不同，炔基亚胺与重氮酯和重氮乙酰胺反应均生成顺式取代的氮杂环丙烷。然而，值得注意的是，这两种重氮化合物从相同对映体的催化剂得到顺式氮杂环丙烷的不同对映体。对映选择性步骤可能的过渡态的理论分析表明，对映体的转变是由于从亚胺的Si面加成转变为Re面加成导致的，这又与前者与E-亚胺反应以及后者与亚胺的Z-异构体反应的转变有关。
