Pd(II)-Catalyzed Aerobic Intermolecular 1,2-Diamination of Conjugated Dienes: A Regio- and Chemoselective [4+2] Annulation for the Synthesis of Tetrahydroquinoxalines

A Pd(II)-catalyted aerobic intermolecular 1,2- diamination of conjugated dienes was developed for the regio and chemoselective preparation of a variety of functionalized tetrahydroquinoxalines, using simple sulfonyl protected o-phenylendiamines as a nitrogen source. This methodology ptovides a direct and efficient synthesis of tetrahydro- quinoxalines. O-2 was used as the stoichimetric oxidant, and reaction conditions were applied to a series of o-phenylendiamines and conjugated dienes. 35 example described, and good yields and selectivities are obtained for the majority of the products.