Mono‐ vs. Dinuclear Gold‐Catalyzed Intermolecular Hydroamidation

Abstract

Mono‐ and dinuclear gold catalysts were investigated in the intermolecular hydroamidation of olefins. Upon activation of [Ph3PAuCl] and [xantphos(AuCl)2] with various silver salts (AgOTf, Ag[BF4], and Ag[SbF6]), diverging reactivity of the resulting cationic gold complexes was observed. It was found that both the binding ability of the counterion and the solvent have a significant impact on the reactivity of the mono‐ and dinuclear complexes.

Dinuclear Gold Complexes Supported by Wide Bite Angle Diphosphines for Preorganization-Induced Selective Dual-Gold Catalysis

“…of AgSbF6, in N,N'-DMF at 60 °C for 5 h led to full conversion and high regioselectivity to B (95-100%), as determined by 1 H Having established that ligands L1 and L2 can facilitate pre-activation of C≡C bonds in a σ,π-fashion, we wondered about their activity in the heterocyclization (intramolecular hydroamination) of urea-functionalized alkyne A. Previously, Paradies and co-workers compared AuCl(Xantphos), Au 2 Cl 2 (Xantphos), and AuCl(PPh 3 ) for the intermolecular hydroamidation of cyclohexene (and analogs thereof) and toluene sulfonamide in the presence of stoichiometric amounts of silver salts as halide abstracting agents [17]. This study concluded that [Au 2 (Xantphos)] 2+ and the corresponding species [Au 2 (Xantphos) 2 ] 2+ , which forms from the former, were both catalytically inactive.…”

“…Dual-gold catalysis, on the other hand, can lead to both σand π-activation (either of the same functional group within a substrate or of two separate functional groups) by two Au centers. The proximity of both Au-centers has occasionally been credited to enhance reactivity [15][16][17]. The prevailing strategy utilizes mononuclear Au(I) complexes to induce this mode of activation (Scheme 1) [18].…”

Synthesis and photophysical properties of multimetallic gold/zinc complexes of (P,N,N,N,P) and (P,N,N) ligands

“…Furthermore, the aromatic scaffold may serve as a reasonable N,N,N-donor for other low-valent transition metals or lanthanides. In the next step, an evaluation of catalytic activities will be explored, for example, in hydroarylation 97 or hydroamidation 98 reactions.…”

Recent Functionalizations of Primary Sulfonamides

“…Under these conditions, the hydroamidation of norbornene, an analogue to cyclohexene, with tosylamide gave 83% isolated yield in only 20 minutes reaction time (Scheme 32). 92…”