Rhodium-Catalyzed 3+3 Annulation of N-Sulfonyl-1,2,3-triazole with a Homoallylic Alcohol for the Synthesis of 1,2-Dihydropyridine.

A general and efficient method for the synthesis of 1,2-dihydropyridine derivatives has been developed through the rhodium-catalyzed formal 3+3 annulation of N-sulfonyl-1,2,3-triazoles with homoallylic alcohols. The reaction demonstrates the chemoselective reactivity of alkene over alcohol followed by ring opening and selective ring closure to afford 1,2-dihydropyridine. The important features include high chemoselectivity, broad functional-group tolerance, and annulation involving C-C and C-N bond formation. In addition, the divergent reactivity of 1,3-diene has also been demonstrated.