Convenient preparation of 4-diazoisochroman-3-imines and 3-subsituted 3,5-dihydroisochromeno[3,4-d][1,2,3]triazoles

A novel and convenient preparation of 4-diazoisochroman-3-imines through the copper(i)-catalyzed cascade reaction of (2-ethynylphenyl)-methanols with sulfonyl azides is described. The synthesized cyclical α-diazo imidates could readily react with a variety of primary amines to furnish 3-substituted 3,5-dihydroisochromeno[3,4-d][1,2,3]-triazoles under catalyst-free conditions.