Regioselective Synthesis of 3-Substituted Isocoumarin-1-imines via Palladium-Catalyzed Denitrogenative Transannulation of 1,2,3-Benzotriazin-4(3H)-ones and Terminal Alkynes.

A palladium-catalyzed denitrogenative transannulation strategy to access various 3-substituted isocoumarin-1-imine frameworks using 1,2,3-benzotriazin-4(3H)-ones and terminal alkynes is described. The reaction is highly regioselective and tolerates a wide range of functional groups. The reaction is believed to proceed via a five-membered palladacycle intermediate extruding environmentally benign molecular nitrogen as a by-product.

Trifluoroacetic Acid-Mediated Denitrogenative -Hydroxylation of 1,2,3-Benzotriazin-4(3)-ones: A Metal-Free Approach.

An efficient trifluoroacetic acid-mediated denitrogenative hydroxylation of 1,2,3-benzotriazin-4(3)-ones is described. This metal-free approach is compatible with a wide range of 1,2,3-benzotriazin-4(3)-ones, affording -hydroxylated benzamides in good to high yields with a short reaction time. The reaction is believed to proceed via a benzene diazonium intermediate.

Palladium/Copper-Catalyzed Denitrogenative Alkylidenation and -Alkynylation Reaction of 1,2,3-Benzotriazin-4(3)-ones.

An efficient palladium-catalyzed approach to access various functionalized ()-3-benzylidene-isoindoline-1-ones and ()-3-benzylidene(imino)isobenzofuranones via a denitrogenative tandem alkynylation/cyclization reaction of 1,2,3-benzotriazin-4(3)-ones with aromatic terminal alkynes is described. Furthermore, a denitrogenative -alkynylation reaction of 1,2,3-benzotriazinones with aliphatic terminal alkynes is also developed. The reaction proceeds through a five-membered azapalladacyclic intermediate with the extrusion of a nitrogen molecule.

Nickel-Catalyzed Denitrogenative Cross-Coupling Reaction of 1,2,3-Benzotriazin-4(3 H)-ones with Organoboronic Acids: An Easy Access to Ortho-Arylated and Alkenylated Benzamides.

A novel nickel-catalyzed approach to synthesize ortho-arylated and alkenylated benzamides in good to high yields via a denitrogenative cross-coupling reaction of 1,2,3-benzotriazin-4(3 H)-ones with organoboronic acids is described. The reaction proceeds through a five-membered azanickelacyclic intermediate with the extrusion of a nitrogen molecule. Moreover, the resulting ortho-arylated benzamides were successfully converted into synthetically useful substituted fluorenones and ortho-arylated benzylamine derivatives in high yields.