Dual catalysis by Cu(I): facile single step click and intramolecular C-O bond formation leading to triazole tethered dihydrobenzodioxines/benzoxazines/benzoxathiines/benzodioxepines

Dual copper catalysis, involving two different reactions, click (alkyne-azide) and carbon oxygen bond formation (aryl iodide secondary alcohol) in a single step, is reported. Synthesis of novel benzodioxines (benzodioxanes), benzoxazines, benzoxathiines and benzodioxepines, which feature benzo-condensed six or seven membered rings containing two hetero-atoms attached to a 1,2,3-triazole, is described. As an extension, such compounds were also synthesised by ring opening of epoxide and cyclisation using Cu(I). All the key products have been characterized by single crystal X-ray crystallography.