This review summarizes the recent achievements of dinuclear gold-catalyzed redox coupling, asymmetric catalysis and photocatalysis. The dinuclear gold catalysts show a better catalytic performance than the mononuclear gold catalysts in certain cases.

The ketone functional group has a unique reactivity in organic chemistry and is associated with a number of useful reactions. Catalytic methods for ketone synthesis are continually being developed. Here, we report a photoredox, nickel and phosphoranyl radical synergistic cross-electrophile coupling of commercially available chemicals, aromatic acids and aryl/alkyl bromides. This allows for concise synthesis of highly functionalized ketones directly, without the preparation of activated carbonyl intermediates or organometallic compounds, and thus complements the conventional Weinreb ketone synthesis. Use of the appropriate photocatalyst, ligand amount and solvents can match the reaction rate required by any simple catalytic cycle. The practicality and synthetic robustness of the reaction are illustrated by the facile synthesis of complex ketones from readily available feedstock chemicals.

A dimeric gold-catalyzed oxidative cross-coupling of arylboronates and arylsilanes has been developed for the synthesis of a large variety of biaryl compounds (>60 examples) and with broad versatility. It can overcome gold-catalyzed o,porientation rules of electron-rich arenes via C-H bond activation. This protocol has excellent functional-group tolerance and flexible synthetic capability for pharmacophores.

A stereodivergent synthesis of five-membered N-heterocycles, such as 2,3-dihydropyrroles, and 2-methylene and 3-methylene pyrrolidines, has been developed through a tandem annulation of amino alkynes with diazo compounds and involves the trapping of in situ formed intermediates. Mechanistic investigations indicate that the copper-catalyzed tandem annulations proceed by allenoate formation and subsequent intramolecular hydroamination. In contrast, the rhodium-catalyzed protocol features a carbenoid insertion into the NH bond and subsequent Conia-ene cyclization.

A concise and one-pot cascade method has been developed to achieve the synthesis of difluoroboron-derivatized curcumins (BF2C). Treatment of 2,4-pentanedione with BF3·OEt2, followed by condensation with aldehydes in the presence of tributyl borate and butylamine at 65 °C in toluene furnished the corresponding symmetric (s-BF2C) and unsymmetric difluoroboron-derivatized curcumins (us-BF2C) in good (60 - 99%) and moderate yields (23 - 42%) within 6 - 12 h, respectively.

A novel ruthenium-catalyzed oxidative alkenylation/annulation cascade reaction is described for synthesizing 3-methyleneisoindolin-1-ones. In the protocol, the N À H imidate is applied efficiently as a directing group in ruthenium-catalyzed C À H activation, generating various 3-methyleneisoindolin-1-ones with high regio-and stereoselectivity in moderate to good yields.

Rhodium-catalyzed intermolecular cyclization of benzamides and diazo compounds via C-H activation has been achieved to construct C-C/C-O bonds for the first time. The process provides a facile approach for the construction of isocoumarins and α-pyrones without the need for high temperature or adding oxidants.

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