An efficient palladium-catalyzed approach to access various functionalized (Z)-3-benzylidene-isoindoline-1-ones and (Z)-3-benzylidene­(imino)­isobenzofuranones via a denitrogenative tandem alkynylation/cyclization reaction of 1,2,3-benzotriazin-4­(3H)-ones with aromatic terminal alkynes is described. Furthermore, a denitrogenative ortho-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. The significance of the reaction is also demonstrated by a one-pot synthesis of (Z)-3-benzylideneisobenzofuran-1­(3H)-one derivatives in good to high yields.

An efficient trifluoroacetic acid-mediated denitrogenative hydroxylation of 1,2,3-benzotriazin-4­(3H)-ones is described. This metal-free approach is compatible with a wide range of 1,2,3-benzotriazin-4­(3H)-ones, affording ortho-hydroxylated benzamides in good to high yields with a short reaction time. The reaction is believed to proceed via a benzene diazonium intermediate. The synthetic utility of the reaction was successfully demonstrated by the preparation of an antimicrobial drug, Riparin C, and benzoxazine-2,4­(3H)-diones in good yields.

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.

An efficient palladium-catalyzed denitrogenative Suzuki-Miyaura type cross-coupling of 1,2,3-benzotriazin-4(3H) ones with organoboronic acid is described. The reaction is compatible with various aryl and alkenyl boronic acids affording ortho-arylated and alkenylated...

The first example of potassium tert-butoxide mediated aerobic hydroxylation of arylboronic acids affording phenols is described.