Geometry Driven Intramolecular Oxidative Cyclization of Enamides: An Umpolung Annulation of Primary Benzamides with Acrylates for the Synthesis of 3-Methyleneisoindolin-1-ones.

A palladium-catalyzed tandem oxidative annulation of primary benzamides with acrylates via intermolecular N-alkenylation followed by intramolecular C-alkenylation yielded a stereoselective synthesis of (E)-3-methyleneisoindolin-1-ones. The study unveils, for the first time, that only E-enamides could undergo intramolecular oxidative cyclization under the optimized conditions to give isoindolinones. The current strategy represents an umpolung strategy when compared to the literature approaches that use benzamides.

Intramolecular Oxidative Arylations in 7-Azaindoles and Pyrroles: Revamping the Synthesis of Fused N-Heterocycle Tethered Fluorenes.

We revealed intramolecular oxidative arylations in 7-azaindoles and pyrroles that, for the first time, provided direct access to 7-azaindole- or pyrrole-fused isoindolines and tetrahydroisoquinolines. In addition, N-benzylation of 7-azaindoles or pyrroles with sterically hindered sec-benzyl alcohols by Mitsunobu reaction followed by intramolecular oxidative arylation allowed access to chiral congeners of fused isoindolines that have little precedence. A new opportunity in the design and synthesis of fluorene-based organic emitters is demonstrated in the preparation of novel fused N-heterocycle tethered fluorenes, including a chiral fluorene architecture.

Palladium-catalyzed regioselective C-2 arylation of 7-azaindoles, indoles, and pyrroles with arenes.

A palladium-catalyzed regioselective C-2 arylation of 7-azaindoles, indoles, and pyrroles with arenes has been developed. This study unveils that a critical substrate dependent acid concentration is essential for achieving exclusive C-2 selectivity as well as mono-arylation in pyrroles. Incongruent to the literature, the protocol uses a reduced volume (at least 5 times) of arenes for workable access to C-2 arylated heterocycles.