A copper-catalyzed reaction of alpha-azido-N-arylamides was found to proceed under an oxygen atmosphere to afford azaspirocyclohexadienones. The present transformation is carried out by a sequence of denitrogenative formation of iminyl copper species from alpha-azido-N-arylamides and their imino-cupration with an intramolecular benzene ring on the amido nitrogen followed by consecutive formation of C=O bonds. The preliminary investigation revealed that molecular oxygen is a prerequisite for achieving the present catalytic cyclization and that one of the oxygen atoms of O(2) was found to be incorporated into the cyclohexadienone moiety.

A copper-catalyzed reaction of alpha-azidocarbonyl compounds under an oxygen atmosphere is reported where nitriles are formed via C-C bond cleavage of a transient iminyl copper intermediate. The transformation is carried out by a sequence of denitrogenative formation of iminyl copper species from alpha-azidocarbonyl compounds and their C-C bond cleavage, where molecular oxygen (1 atm) is a prerequisite to achieve the catalytic process and one of the oxygen atoms of O(2) was found to be incorporated into the beta-carbon fragment as a carboxylic acid.

A copper-catalyzed synthesis of phenanthridine derivatives was developed starting from biaryl-2-carbonitriles and Grignard reagents. The present transformation is carried out by a sequence of nucleophilic addition of Grignard reagents to biaryl-2-carbonitriles to form N-H imines and their Cu-catalyzed C-N bond formation on the aromatic C-H bond, where molecular oxygen is a prerequisite to achieve the catalytic process.

Copper-catalyzed benzylic C-H oxygenation under an oxygen atmosphere was developed starting from carbonitriles and Grignard reagents via N-H imine intermediates. The present process is characterized by the following two-step sequence in a one-pot manner: (1) addition of Grignard reagents to carbonitriles to form N-H imines and (2) benzylic C-H oxygenation (C═O bond formation) triggered by 1,5-hydrogen atom transfer with transient iminyl copper species.

No abstract