Enantioselective Alkynylbenzaldehyde Cyclizations Catalyzed by Chiral Gold(I) Acyclic Diaminocarbene Complexes Containing Weak Au–Arene Interactions

Abstract

Hold me close: Highly enantioselective catalysis of tandem acetalization/cycloisomerization reactions of o‐alkynylbenzaldehydes has been achieved using gold complexes of chiral acyclic diaminocarbene ligands that have electron‐deficient aryl substituents. X‐ray crystallography and DFT calculations implicate weak gold‐arene interactions—absent in the case of simple phenyl substituents—that define the chirality of the substrate binding site.

Supra-molecular synthons based on gold…π(arene) interactions

“…Similar intra-molecular Au…π(arene) interactions have been noted previously in other systematic investigations, for example, in cationic phosphanegold compounds of simple η 2 -bound arenes [29] as well as in neutral acylic diaminocarbene goldchlorido structures [30]. Attention is now directed to deliberately tailoring of ring-bound substituents to promote the formation of intra-molecular Au…π(arene) interactions.…”

Synthesis of axially chiral gold complexes and their applications in asymmetric catalyses

“…Very few efficient chiral NHC–gold catalysts have been known up to the year of 2013. So far, several axially chiral NHC–gold catalysts based on binaphthyl skeleton such as 1 and 2 [46,49] have been reported with good to excellent chiral inductions in asymmetric gold catalysis (Fig. 1).…”

Gold(I)‐Catalyzed Asymmetric Desymmetrization of meso‐Alkynyl Diols and Kinetic Resolution of the Corresponding dl‐Diols: Effects of Celite Filtration and Silver Salts

“…Any combination of axially chiral diphosphine(AuCl) 2 and silver salt resulted in excellent enantioselectivity. Thus, meso-2-alkynylbenzenediols 1 underwent asymmetric desymmetrization through the use of a combination of an axially chiral diphosphine(AuCl) 2 precatalyst 2 and a silver salt to give optically active 1H-isochromene derivatives [15] with high enantioselectivities in good yields.…”