Chiral N-Alkylfluorenyl-Substituted N-Heterocyclic Carbenes in the Gold(I)-Catalyzed Enantioselective Cycloisomerization of 1,6-Enynes.

A series of chiral *Flu-NHC-gold(I) complexes, where *Flu-NHC is an N-heterocyclic carbene (imidazolin-2-ylidene or benzimidazolin-2-ylidene) bearing a chiral 9-alkyl-9-fluorenyl N-substituent and a 2,6-diisopropylphenyl or benzyl N'-substituent, were straightforwardly prepared in few steps from readily available 2,6-diisopropylamine, imidazole or benzimidazole. The chirality of the N-substituent lies in the presence of a chiral alcoholic alkyl chain on the fluorenyl, which results from the opening of commercially available chiral styrene oxide, yielding to a 2-hydroxy-2-phenylethyl or a 2-hydroxy-1-phenylethyl group. Four [AuCl(*Flu-NHC)] complexes were tested as precatalysts in an enantioselective cycloisomerization of a 1,6-enyne.