1,6-Addition of vinyl p-quinone methides with cyclic sulfamidate imines: Access to 4-hydroxyaryl-2,6-diarylpyridines

A simple and powerful one-pot regioselective 1,6-addition elimination-6π-aza-electrocyclization-aromatization reaction of vinyl/dienyl-substituted para-quinone methides with a bunch of cyclic sulfamidate imines as 2C1N synthons promoted by DABCO as a solid organobase in an open-atmosphere is reported first time. The above C-C and C-N bonds formation process provides good to high yields of a wide breadth of symmetrically and unsymmetrically 2,4,6-trisubstituted pyridines possessing a sterically hindered phenolic moiety at C4-position with a broad substrate scope. This domino [3+3] cyclization reaction allows several compatible functionalities under metal-free conditions. Finally, the large-scale synthesis of pyridine derivative has been demonstrated