β-Cyclodextrin–NHC–Gold(I) Complex (β-ICyD)AuCl: A Chiral Nanoreactor for Enantioselective and Substrate-Selective Alkoxycyclization Reactions
Coralie Tugny, Natalia Del Rio, Mehdi Koohgard, Nicolas Vanthuyne, Denis Lesage, Kajetan Bijouard, Pinglu Zhang, Jorge Meijide Suárez, Sylvain Roland, Étienne Derat, Olivia Bistri‐Aslanoff, Matthieu Sollogoub, Louis Fensterbank, Virginie Mouriès‐Mansuy
Abstract
NHC-capped β-cyclodextrin (β-ICyD) was used as a ligand for gold-catalyzed alkoxycyclization reactions. The cavity was found to be responsible for a triple selectivity: (i) the asymmetric shape of the cavity of β-ICyD induced highly stereoselective cyclizations, (ii) the shape of the interior favored the formation of a six-membered ring in the absence of a nucleophile, and finally, (iii) the encapsulation of the metal inside the cavity disfavored the addition of sterically hindered alcohols. Highly enantioselective and substrate-selective alkoxycyclizations of enynes are therefore promoted by the cavity-based molecular reactor (β-ICyD)AuCl.