1-Aminobenzotriazole functionalisation using directed metallation: new routes to chromanes and chromenes using intramolecular benzyne trapping by alcohols

Metallation of 1-(tert-butoxycarbonylamino)benzotriazole 8 leads to the dia nionic species 9 which undergoes smooth reactions with a range of electroph iles, under appropriate conditions. The derived iodide 30 undergoes efficie nt Sonogashira coupling with a range of alk-1-yn-3-ols to provide the expec ted arylalkynes 33, total or partial reduction of which leads to the arylpr opanols 34 and the (Z)-allylic alcohols 40 respectively. N-Deprotection and exposure to N-iodosuccinimide then led to smooth benzyne generation and in tramolecular trapping by the hydroxy functions with iodine incorporation to give the iodochromanes 35 and iodochromenes 41 respectively, in respectabl e overall yields.