Benzimidazolium‐ and Benzimidazolilydene‐Capped Cyclodextrins: New Perspectives in Anion Encapsulation and Gold‐Catalyzed Cycloisomerization of 1,6‐Enynes

Abstract

A new way of introducing a N-heterocyclic carbene cap onto cyclodextrins has been devised. The benzimidazolium intermediates were found to behave as receptors towards cavity matching anions. The corresponding C₁ - and C₂ -symmetrical regioisomeric carbene gold(I) complexes have been tested in a benchmark asymmetric cycloisomerization of 1,6-enynes. Up to 50 % ee was achieved for the enantioselective cycloisomerization of N-allyl-4-methyl-N-(3-phenylprop-2-yn-1-yl)benzenesulfonamide.