Steric tuning of C2-symmetric chiral N-heterocyclic carbene (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.