Ag2CO3-catalyzed difunctionalization of alkynes via a radical phosphonation and C-H functionalization tandem process was developed to synthesize various 3-phosphonated coumarins in moderate to high yields with high regioselectivity. A catalytic amount of cheap and nontoxic silver salt was employed in the domino C-P and C-C formation of alkynoates for the first time. Mechanistic studies indicate that the reaction pathway might proceed via the generation and cyclization of a phosphonated vinyl radical intermediate.

A novel Pd(II)-catalyzed dehydrogenative cross-coupling reaction between coumarins and H-phosphonates has been developed to give the corresponding 3-phosphonated products in moderate to good yields with high selectivity.

In visible light, sulfoximidoyl-containing hypervalent iodine reagents react with aryl alkynes to give N-α-ketoacylated sulfoximines in good to high yields. The process is metal- and base-free, providing the diketonic products without the use of highly oxygenated reagents such as peroxides. Results from mechanistic investigations suggest the intermediacy of radicals and reveal the importance of molecular oxygen.

A new and efficient metal-free tandem acylation/cyclization of alkynoates with aldehydes was developed for the synthesis of 3-acyl-4-arylcoumarins. The reaction was achieved by the addition of acyl radical to alkynes and a C-H bond functionalization to form two new C-C bonds simultaneously.

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Reactions of difluoroiodotoluene with NH-sulfoximines provide new hypervalent iodine(III) reagents, which photocatalytically transfer a fluoro and a sulfoximidoyl group onto styrenes with high regioselectivity. The substrate scope is broad with respect to both sulfoximines and olefins. Following an operationally simple protocol, a large library of fluorinecontaining N-functionalized sulfoximines can be accessed. Results from mechanistic investigations revealed the importance of radical intermediates.

A novel and efficient method for the synthesis of α-cyanomethyl-β-dicarbonyls in moderate to excellent yields is developed by using inactive CH3CN and simple 1,3-dicarbonyls. A radical mechanism is proposed under the ESI-MS (electrospray ionization mass spectrometry) analysis results of control experiments.

Silver-catalyzed carbonphosphonation of α,α-diaryl allylic alcohols is achieved. A series of γ-ketophosphonates with different substituents were readily obtained. The mechanistic study indicated that the reaction was initiated by the addition of P-radicals, which sequentially undergo 1,2-migration of an aryl group to form C(Ar)-C(sp(3)) bonds.