Reactivity of Vinyl Epoxides/Oxetanes/Cyclopropanes toward Arynes: Access to Functionalized Phenanthrenes

Visible Light-Promoted Diazoacetates and Nitriles Generating Nitrilium Ions Trapped by Benzotriazoles and Carboxylic Acids

A visible light-promoted generation of nitrilium ions from diazoacetates and nitriles has been developed. The reaction utilized visible light transformation of diazoacetates to the free carbene that could be trapped by nitriles to generate nitrilium ions, followed by nucleophilic attack on the benzotriazoles and carboxylic acids. This protocol provides an efficient and practical approach to N-imidoylbenzotriazoles and diacylglycine esters in good to excellent yields.

Palladium-Catalyzed Carbonylative [5+1] Cycloaddition of N-Tosyl Vinylaziridines: Solvent-Controlled Divergent Synthesis of α,β- and β,γ-Unsaturated δ-Lactams

A palladium-catalyzed carbonylative [5+1] cycloaddition of N-tosyl vinylaziridines with CO has been developed. This protocol affords an efficient and practical approach for solvent-controlled divergent synthesis of α,β-unsaturated δ-lactams in dimethylformamide and β,γ-unsaturated δ-lactams in tetrahydrofuran in good to excellent yields. Significantly, the step- and atom-economical reactions are more regioselective toward [5+1] cycloaddition than toward [3+1] cycloaddition.

Palladium-Catalyzed Regioselective [5 + 1] Annulation of Vinyl Aziridines/Epoxides with ClCF2COONa

Palladium-catalyzed regioselective [5 + 1] annulation reactions of vinyl aziridines/epoxides with ClCF₂COONa have been developed. Significantly, vinyl aziridines/epoxides act as heteroatom-containing five-atom synthons, and commercially available and cheap ClCF₂COONa acts as the source of carbonyl serving as a difluorocarbene precursor. This protocol provides an efficient and practical method for the synthesis of δ-lactams and δ-lactones in good yields.

Visible-Light-Induced 1,6-Enynes Triggered C-Br Bond Homolysis of Bromomalonates: Solvent-Controlled Divergent Synthesis of Carbonylated and Hydroxylated Benzofurans

Visible-light-induced 1,6-enyne-triggered C-Br bond homolysis of bromomalonates has been developed. This transition-metal-free, photocatalyst-free, and oxidant- and additive-free protocol affords an efficient approach for divergent synthesis of carbonylated and hydroxylated benzofurans from 1,6-enynes and bromomalonates under mild conditions. Significantly, mechanistic studies reveal that the homolysis of C-Br bonds appears to experience an energy-transfer pathway, and the atom-transfer radical addition products are the key intermediates to generate carbonylated and hydroxylated benzofurans.