Treatment of alk-2-ynyl derivatives of enantiopure phenylglycidol with NaN3 triggers a cascade reaction consisting of stereospecific and regioselective epoxide ring opening followed by intramolecular azide-alkyne cycloaddition under strictly metal-free conditions. This simple one-pot procedure allows a fast buildup of molecular complexity, generating a wide array of triazolooxazepinols, triazolodiazepinols, and triazolothiazepinols.
![Copper-free intramolecular alkyne-azide cycloadditions leading to seven-membered heterocycles](https://www.iciq.org/wp-content/uploads/2014/03/Copper-free-intramolecular_5044.gif)