A general access to organogold(iii) complexes by oxidative addition of diazonium salts

Abstract

At room temperature under mild photochemical conditions, namely irradiation with a simple blue light LED, gold(i) chloro complexes of both phosphane and carbene ligands in combination with aryldiazonium salts afford arylgold(iii) complexes. With chelating P,N-ligands cationic six- or five-membered chelate complexes were isolated in the form of salts with weakly coordinating counter anions that were brought in from the diazonium salt. With monodentate P ligands or N-heterocyclic carbene ligands and diazonium chlorides neutral arylgold(iii) dichloro complexes were obtained. The coordination geometry was determined by X-ray crystal structure analyses of representative compounds, a cis arrangement of the aryl and the phosphane ligand at the square planar gold(iii) center is observed.

Dual gold and photoredox catalysis: visible light-mediated intermolecular atom transfer thiosulfonylation of alkenes

“…On the basis of the abovementioned results and previous reports, 12 a tentative proposed mechanism is shown in Scheme 3. Irradiation of Ru(bpy) 3 2+ generates a long-lived photoexcited state Ru(bpy) 3 2+* , which undergoes a single-electron transfer reaction with cationic IPrAu( i ) to initiate the catalytic cycle and provide Ru(bpy) 3 3+ and the highly active IPrAu(0), which can reduce PhSO 2 SCF 3 to form IPrAu( i )SCF 3 ( 8 ) and a benzenesulfonyl radical, which when added to styrene affords an alkyl radical.…”

“…12 k Recently, Hashmi reported an aryldiazonium salts mediated Au( i ) to Au( iii ) transformation upon irradiation with blue LED in the absence of a photosensitizer. 12 q In all these reactions, 12 the same aryldiazonium salts were used. The development of new gold/photoredox catalysis mode is highly desirable.…”

Visible light-induced transition metal-catalyzed transformations: beyond conventional photosensitizers

“…The authors mentioned that the efforts to isolate 101 were unsuccessful. Fortunately in their follow-up work, 41 Hashmi reported a general access to similar Au(III) complexes via a visible light-induced oxidative addition of aryl diazonium salt with P,N-bidentate ligands and other monodentate ligands, which indirectly confirms 101 as a valid intermediate. Coordination of alkyne substrate with 101 results in formation of complex 102 , which upon intermolecular attack by methanol affords vinyl Au complex 103 .…”

Gold‐Catalyzed Cross‐Coupling Reactions: An Overview of Design Strategies, Mechanistic Studies, and Applications

“…Further, the visible-light-mediated Suzuki-type coupling between aryl boronic acids with aryl diazonium salts was investigated in the presence of catalytic amountso fA uc omplexes (Scheme 55 d). [287] Chem.E ur.J.2020, 26,1442-1487 www.chemeurj.org 2019 Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim membered chelated Au III complexes, thereby providing direct evidencef or the photochemical oxidation of Au. Nevertheless, the CÀCb ond reductive elimination could be suppressed in five-or six-memberedc helate Au III complexes.T o test this hypothesis, Hashmi'sg roup studied the visible-lightassisted oxidation of Au I complexes containing chelating( P, N)ligands, phosphanes, and NHC ligands with aryl coupling partners (Scheme 56).…”

“…[286] Mechanistically,a fast C(sp 2 )ÀC(sp 2 )r eductivee limination from the Au III intermediate prohibited the isolation of the latter species. [287] Ar ecent computational study based on DFT calculations predicted that an initial charge-transfer complex would be formed by the reaction of the Au I catalystw ith the aryl diazonium salt. The reaction led to isolable five-and six-Scheme54.…”