(P,C) Cyclometalated Gold(III) Complexes: Highly Active Catalysts for the Hydroarylation of Alkynes

Abstract

The first catalytic application of well‐defined (P,C) cyclometalated gold(III) complexes is reported. The bench‐stable bis(trifluoroacetyl) complexes 2 a,b perform very well in the intermolecular hydroarylation of alkynes. The reaction is broad in scope, it proceeds within few hours at 25 °C at catalytic loadings of 0.1–5 mol %. The electron‐rich arene adds across the C≡C bond with complete regio‐ and stereo‐selectivity. The significance of well‐defined gold(III) complexes and ligand design are highlighted in a powerful but challenging catalytic transformation.

Recent Advances in Gold(III) Chemistry: Structure, Bonding, Reactivity, and Role in Homogeneous Catalysis

“…as competent catalyst for the hydroarylation of internal alkynes with electron-rich arenes to give trans-styrene derivatives (Scheme 143). 544 The bis-trifluoroacetate Au(III) complex 332 showed good catalytic activities and high regio-and stereoselectivity in CH 2 Cl 2 /trifluoroacetic acid mixtures. No reactivity was observed in the absence of the acid.…”

Gold-catalyzed hydroarylation reactions: a comprehensive overview

“…Amgoune and Bourissou's group described the hydroarylation of alkynes using a highly active (P, C) cyclometalated gold( iii )-catalyst (Scheme 73). 94 The reaction occurred between aromatic compound 2 and the alkyne 174 under the optimized reaction conditions of 5 mol% [L 20 Au(OAc F ) 2 ] catalyst and dichloromethane at 25 °C for 0.5–24 h to form the favored product 236 in 76–99% yields. Two types of dichloromethane/trifluoroacetic acid ratios (20/1 and 1/4) were used in this process.…”

Base‐Triggered Oxidative Addition to Gold

“…It provides straightforward access to (P,C)‐cyclometalated Au(III) complexes which are hardly accessible by the classical C−H activation route due to the propensity of phosphines to be oxidized by Au(III) salts [6] . The (P,C)Au(III) complexes display rich chemistry, from unprecedented elementary reactivity at gold (migratory insertion, β‐H elimination) [7] to Au(III) catalysis (intermolecular hydroarylation of alkynes) [8] . They also proved efficient and versatile scaffolds to stabilize and authenticate original complexes (C−H agostic, π‐arene and π‐allyl complexes) [9]…”