Steric tuning of C2-symmetric chiral N-heterocyclic carbene in gold-catalyzed asymmetric cyclization of 1,6-enynes

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.

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