Alkynyl oxime ether underwent a gold-catalyzed domino reaction involving cyclization and subsequent Claisen-type rearrangement to afford trisubstituted isoxazoles in a direct, efficient, and regioselective manner. The products were successfully applied to the synthesis of unusual heterocycles as an illustration of the potential utility of the reaction.

Transition metal-catalyzed aminocarbonylation of aryl halides with CO and amines, pioneered by Heck and co-workers in the 1970s, is among the most commonly employed reactions to make aromatic amides. A catalyst-free aminocarbonylation of aryl iodides with CO and amines, which simply uses photoirradiation conditions by Xe-lamp, has now been developed. This methodology shows broad functional-group tolerance, including that of heteroaromatic amides. A hybrid radical/ionic chain mechanism, involving electron transfer from zwitterionic radical intermediates generated by nucleophilic attack of amines to aroyl radicals, is proposed.

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An atom-economical, catalytic, and regioselective synthesis of 3,4,5-trisubstituted isoxazoles has been successfully developed. Treatment of O-arylmethyl alkynyl oxime ethers with 5 mol % of Cu(OTf)(2) in chlorobenzene at reflux gave 4-arylmethylisoxazoles in good to excellent yields via the sequential intramolecular addition of the oxime moiety to the alkyne with subsequent 1,3-migration of the arylmethyl group.

Radical biaryl coupling of iodoarenes and benzene can be effectively promoted by tetrabutylammonium cyanoborohydride with air under photoirradiation conditions using a Xe lamp. The utility of this methodology is highlighted by its functional group tolerance and chemoselectivity.