Gold -catalyzed hydroarylation

Reactions by Arenes In 2000, the first evidence of a gold-catalyzed hydroarylation of a, 3-unsaturated alkenes was reported by Hashmi et al. in their research with furans. In this publication, they proposed two possible mechanisms for the process ... 

Gold-catalyzed Hydroarylation of Alkynes 157 Manfred T. Reetz and Knut Sommer... 

Representative procedure for the gold-catalyzed hydroarylation of alkynes. l-(3-Hydroxy-2,4,6-trimethylphenyl)-l-(4-methoxyphenyl)ethend ... 

Representative procedure for the intramolecular gold-catalyzed hydroarylation of allenes. (R,E)-Methyl 4-[(R)-8-ethyl-5,6,7,8-tetrahydroindolizin-8-yl]-2-methylbut-3-... 

Electron-rich phenyl rings are also suitable nucleophiles for the intramolecular gold-catalyzed hydroarylation of allenes. Thus, dihydroquinoline and chromene derivatives are accessible by treating allenic anilines or allenic aiylethers with a cationic gold catalyst (Scheme 4-14). Because of the limited stability of... 

The intramolecular gold-catalyzed hydroarylation of alkynes is a well-established methodology, which allows the synthesis of a broad range of complex products. Some examples are the synthesis of A -tosyl-1,2-hydroquinolines [122], cinnoline derivatives [123], phenantrenes [124], coumarines [117], and pyrrolo[l,2-a]quini-... 

As shown in Equation (30), furan reacted with ethyl acetylenecarboxylate under gold-catalyzed conditions to form the hydroarylation product that contained a (Z)-alkene selectively <2003EJO3485>. 

The gold-catalyzed intermolecular hydroarylation of alkynes (or alkenylation of arenes) leads to 1,1-disubstituted alkenes (equation 91) 240-243 1 2-Disubstituted derivatives are obtained from alkynes with electron-withdrawing groups (equation 92). ... 

Hydroarylation can also be mediated by Au(I) and Au(III) (Scheme 33) (384). In the case of aryl substituted alkynes, the Au(III) Ji complex undergoes electrophilic aromatic substitution with the electron-rich arene to give aLkenyl-Au(III) complex, which is immediately protonated by the H generated upon C C bond formation. For the Au(I)-catalyzed hydroarylation, the cationic gold complex k coordinates the alkyne, with subsequent nucleophilic attack by the arene from the opposite face leading to an alkenyl-gold complex, which is protonated to the desired products. The nature of the reaction causes the regioselectivity of this reaction to be sensitive to electronic rather than steric factors. 

The intermolecular hydroarylation of indoles or pyrroles with alkynes in the presence of cationic gold(I) catalysts leads to 2 1-adducts With (Z)-2-en-4-yn-l-ols as an unsaturated reaction partner, indoles are converted into dihydrocyclohepta[ )] indoles in a one-pot reaction sequence that involves a gold-catalyzed intermolecular Friedel-Crafts alkylation followed by an intramolecular hydroarylation (Scheme 4-9). ... 

A-vinylindoles took place. Moreover, the gold-catalyzed cyclization of 2-alkynylanilines can be combined with a gold-catalyzed Michael addition to enones, which afforded 3-alkylated indoles with good yield. Gold-catalyzed hydroamination/hydroarylation cascades of polyenyne-substituted anilines leading to condensed aromatics have been described recently. ... 

Indeed, Cu can be used in combination with tungstophosphoric acid to realize solvent-free acid-catalyzed hydroarylation and hydroamination of alkynes to give the Markovnikov products with a variety of arylamines [211]. Furthermore, gold catalysts have been used extensively with acid additives for a variety of amine and protected amine substrates [120,212]. More recently, Bertrand [189] was able to illustrate the useful apphcation of his [(CAACjAulBlCgFj) complex for intermolecular alkyne hydroamination with both primary and secondary amines (Table 15.14). 

The sequential intramolecular hydroarylation of alkynes is applied to the synthesis of structurally complex extended x-systems. The gold-catalyzed sequential intramolecular hydroarylation of triynes followed by aromatization with DDQ proceeded to give triaryl-substituted diacenaphtho[l,2-y l, 2 -l] fluoranthenes, which can be used for organic light-emitting devices (Scheme 21.49) [55]. 

Very recently, the enantio- and diastereoselective synthesis of an S-shaped double azahelicene has been achieved via the gold-catalyzed sequential intramolecular alkyne hydroarylation (Scheme 21.51) [57]. 

First gold-catalyzed reaction of aiienes, ketones as nucleophiles and step-wise two-fold hydroarylation... 

Scheme 1.7 Formation of cinnoline by gold(I)-catalyzed hydroarylation of iV-propargyl-A/ -arylhydrazines...

Study on this allene hydroarylation reaction, the presence of dinuclear gold-gold and gold-silver intermediates was suggested (Scheme 18.19), together with vinyl gold complex, in the gold(I)-catalyzed hydroarylation [18],... 

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