Cobalt(III)-Catalyzed Regio- and Chemoselective [4 + 2]-Annulation of N -Chlorobenzamides/Acrylamides with 1,3-Dienes at Room Temperature.

Co(III)-catalyzed regio- and chemoselective redox-neutral C-H annulation of arylamides/acrylamides with 1,3-dienes is described. The present annulation reaction was well suited with a less-reactive 1,3-butadiene. By employing this protocol, pharmaceutically important 3,4-dihydroisoquinolinones were synthesized in good yields. Furthermore, the prepared 3,4-dihydroisoquinolinones were converted into highly important oxirane derivatives in good yields. A plausible mechanistic cycle is proposed and supported by a competition experiment and kinetic isotopic effect (KIE) studies.