Catalytic Gold Chemistry: From Simple Salts to Complexes for Regioselective C−H Bond Functionalization

Abstract

Gold coordinated to neutral phosphines (R 3 P), Nheterocyclic carbenes (NHCs) or anionic ligands is catalytically active in functionalizing various CÀ H bonds with high selectivity. The sterics/electronic nature of the studied CÀ H bond, oxidation state of gold and stereoelectronic capacity of the coordinated auxiliary ligand are some of the associated selectivity factors in gold-catalyzed CÀ H bond functionalization reactions. Hence, in this review a comprehensive update about the action of different types of gold catalysts, from simple to sophisticated ones, on CÀ H bond reactions and their regiochemical outcome is disclosed. This review also highlights the catalytic applications of Au(I)-and Au(III)species in creating new opportunities for the regio-and siteselective activation of challenging CÀ H bonds. Finally, it also intends to stress the potential applications in selective CÀ H bond activation associated with a variety of heterocycles recently described in the literature.

Direct Regioselective Hydro(hetero)arylation/Cyclocondensation Reactions of β-(2-Aminophenyl)-α,β-ynones by Means of Transition-Metal Catalysis/Brønsted Acid Synergism: Experimental Results and Computational Insights

“…The vital importance in organic synthesis of sustainable synthetic methodologies has led to the development of numerous synthetic strategies for C–H functionalization reactions that have higher efficiency and minimal chemical waste . Despite remarkable advances, C–H bond functionalization reactions are still highly changeling for synthetic organic transformations . As a consequence of the prevalence of the quinoline scaffold in a large variety of pharmacologically active compounds, in naturally occurring products as well as materials, dyes, and chemosensors, the development of more sustainable and practical synthetic methodologies of this derivative remains a significant goal .…”

Enantioselective C−H Functionalization Reactions under Gold Catalysis

“…The main achievements in gold-catalyzed CÀ H functionalization reactions have been already summarized in few reviews. [51,52,[83][84][85][86][87][88][89] However, a review that solely focuses on the developments in the field of enantioselective CÀ H functionalization reactions under gold catalysis is missing by far.…”

“…Interestingly, gold‐catalyzed C−H functionalization reactions often provide complementary chemo‐ and regioselectivities as compared to other transition metal‐catalyzed processes, [82] and therefore recently started gaining significant attention from organic and organometallic chemistry community. The main achievements in gold‐catalyzed C−H functionalization reactions have been already summarized in few reviews [51,52,83–89] . However, a review that solely focuses on the developments in the field of enantioselective C−H functionalization reactions under gold catalysis is missing by far.…”

Noncovalent Synergy: Aurophilicity and Aryl Stacking in Bis(gold(I)aryl)-dmpm Complexes

“…3,4 The origin of these interactions is said to be mainly dispersion, but other mechanisms like electrostatic multipole interactions or induction also contribute. 5−9 The strength of aurophilic interactions is often compared with that of hydrogen bonds; 10 thus, aurophilicity plays a crucial role in the structural, 1,11 photophysical, 3,12,13 and catalytic 14,15 chemistry of gold complexes. In general, dinuclear gold(I) complexes are described as either unsupported, semi-supported, or fully supported (Scheme 1) depending on the number of involved linking ligands (0−2).…”

“…Aurophilicity as a concept was introduced for attractive interactions between gold atoms in the oxidation state +I with typical Au–Au distances between 2.50 and 3.50 Å. , Later, the concept was further developed, and the term metallophilic attraction was coined to include interactions between metal atoms in the d 8 , d 10 , and s 2 states. , The origin of these interactions is said to be mainly dispersion, but other mechanisms like electrostatic multipole interactions or induction also contribute. − The strength of aurophilic interactions is often compared with that of hydrogen bonds; thus, aurophilicity plays a crucial role in the structural, , photophysical, ,, and catalytic , chemistry of gold complexes. In general, dinuclear gold­(I) complexes are described as either unsupported, semi-supported, or fully supported (Scheme ) depending on the number of involved linking ligands (0–2) .…”