H‐Bonded Counterion‐Directed Catalysis: Enantioselective Gold(I)‐Catalyzed Addition to 2‐Alkynyl Enones as a Case Study
作者:Àlex Martí、Marc Montesinos‐Magraner、Antonio M. Echavarren、Allegra Franchino
DOI:10.1002/ejoc.202200518
日期:2022.10.13
H-bonded counterion-directed catalysis has been applied to the enantioselective tandem cycloisomerization-addition to 2-alkynyl enones. The addition of C-, N- or O-centered nucleophiles catalyzed by a phosphinosquaramide Au(I) chloride/chiral Ag(I) phosphoramidate system afforded bicyclic furans in moderate to excellent yield and enantioselectivity (28 examples, 59–96 % yield, 62 : 38 to 95 : 5 er)
cooperative gold(I)/DMAP system catalyzes the (2 + 3) cycloadditions of yne–enones with oxindole-derived Morita–Baylis–Hillman (MBH) carbonates, yielding diverse bispiro-cyclopentene oxindole products. The mild, scalable protocol demonstrates broad substrate scope and excellent chemo- and diastereoselectivity. Mechanistic study reveals pivotal roles of both catalysts in the unique (2 + 3) cycloaddition. This
A Class of Chiral‐Bridged Biphenyl Monophosphine Ligands with Benzofuran Moiety and The Application in Diastereo‐ and Enantioselective Au(I)‐Catalyzed Cycloaddition
A class of novel chiral‐bridged biphenyl monophosphine ligands with a benzofuran moiety (He‐phos) has been successfully synthesized and reported. These ligands exhibited good performance in the gold‐catalyzed enantioselective cycloaddition reaction of 2‐(1‐alkynyl)‐2‐en‐1‐ones with nitrones, resulting in the successful preparation of a series of polyaryl‐substituted heterocyclic compounds with high enantioselectivities (up to 99% yield, 98% ee). The wide substrate adaptability (53 examples) and mild reaction conditions demonstrate the practicability of He‐phos in this reaction.