Synthesis of 2,4‐dihydrochromeno[3,4‐d][1,2,3]triazoles and 5‐(2H‐chromen‐3‐yl)‐1H‐tetrazoles via regioselective 1,3‐dipolar cycloaddition of 2H‐chromene‐3‐carbonitriles with NaN3

Abstract

AbstractConjugated cyano cyclo‐olefins modified as highly regioselective dipolarophiles in 1,3‐dipolar cycloaddition with NaN3 to synthesize corresponding fused 1,2,3‐triazole and 1H‐tetrazole derivatives. The first example of catalytic 1,3‐dipolar cycloaddition of NaN3 with 2H‐chromene‐3‐carbonitriles and subsequent elimination/cyclization of cyano functionality is designated. In presence of catalytic amount of p‐TSA or AgNO3, 2H‐chromene‐3‐carbonitriles react with NaN3 discretely producing 2,4‐dihydrochromeno[3,4‐d][1,2,3]triazoles or 5‐(2H‐chromen‐3‐yl)‐1H‐tetrazoles respectively, in good to excellent yields (i. e. 51–88 % or 85–97 %) with high regioselectivity and wide substrate scope adequacy.