Steric tuning of C2-symmetric chiral N-heterocyclic carbene in gold-catalyzed asymmetric cyclization of 1,6-enynes
作者:Ken-ichi Yamada、Yasumasa Matsumoto、Khalid B. Selim、Yasutomo Yamamoto、Kiyoshi Tomioka
DOI:10.1016/j.tet.2012.03.107
日期:2012.6
Steric tuning of C2-symmetric chiralN-heterocycliccarbene (NHC) was performed in Au(I)-catalyzed asymmetric cyclization of 1,6-enyne. Higher enantioselectivity was realized when chiral NHC–AuCl/AgSbF6 catalysts whose N-substituent on the NHC overlays the Au–Cl bond was utilized.