A simple and efficient one-pot annulation of arylidenones, alkynes, and nitriles in the presence of BF3.OEt2 is described. A highly functionalized variety of N-substituted pyridine fused-, chromeno and pyrano derivatives obtained with satisfactory yields under mild reaction conditions. The method was proven to be valid for the synthesis of the diverse library of chromeno [3,4-c]pyridines, thiochromeno[3,4-c]pyridines, pyrano[3,4-c]pyridines, thiopyrano[3,4-c]pyridine derivatives from readily accessible substrates. This experimentally simple protocol provides structurally complex, biologically relevant heterocycles in a one-pot operation.
Ashitha K. T, Praveen Kumar V, Fathimath Salfeena C. T, B. S. Sasidhar*
Journal of Organic Chemistry, 2017