Novel routes to 1‐aryl‐1,4‐dihydro‐3(2 H )‐isoquinolinones and 2‐substituted or 2,3‐disubstituted benzofurans by intramolecular cyclizations

N ‐(α‐Benzotriazolylalkyl)arylacetamides, readily available from an arylacetamide, an aldehyde and benzotriazole, undergo intramolecular cyclization under acidic conditions to give 1‐aryl‐1,4‐dihydro‐3(2 H )‐isoquinolinones in good to excellent yields. Similarly, 2‐(benzotriazol‐1‐yl)‐2‐( o ‐hydroxyphenyl)ethanols, obtained by lithiation of 2‐(benzotriazol‐1‐ylmethyl)phenols followed by quenching with aldehydes or ketones, eliminate a molecule of water and a molecule of benzotriazole yielding 2‐substituted and 2,3‐disubstituted benzofurans.