Planar Chirality Change in Dediazoniation Reactions of Paracyclophanes and Mechanistic Implication
作者:Fuyan He、Yudao Ma、Lei Zhao、Wenzeng Duan、Jianqiang Chen、Chun Song
DOI:10.1021/ol302510t
日期:2012.11.2
Dediazoniation reactions of (Sp)-4-bromo-13-[2.2]paracyclophanyldiazonium fluoborate 2a through a heterolytic cleavage process gave products with partial racemization. In contrast, dediazoniation reactions of (Sp)-2a undergoing a nonheterolytic cleavage process afforded products with retention of configuration. A key intermediate, the bromonium cation B, caused the racemization. The unexpected racemization
(S p)-4-溴-13- [2.2]对环吡啶基重氮氟硼酸酯2a通过杂解裂解反应进行脱氮反应,得到部分消旋的产物。与此相反,(的dediazoniation反应小号p) - 2a中经历nonheterolytic裂解方法得到的产品具有配置的保持。关键中间体溴阳离子B引起了外消旋作用。出乎意料的消旋作用允许探究脱氮反应的机理。