Electrophilic Cyclization of 2‐Aminophenylprop‐1‐yn‐3‐ols into 3‐Iodo‐6‐(aryldiazenyl)quinolines by Using a One‐Pot Azo‐Coupling and Iodocyclization Sequence

Abstract

6‐(Aryldiazenyl)‐3‐iodoquinolines were prepared from readily available 2‐aminoaryl propargyl alcohols, aryldiazonium salts, and molecular iodine. This three‐component one‐pot process proceeded through sequential azo‐coupling, regioselective iodocyclization, and aromatization reactions to yield the corresponding quinoline derivatives. In the absence of iodine, Ca(OTf)2 was used to promote the azo‐coupling and azacyclization reactions, which furnished the respective 6‐aryldiazenylquinolines. In addition, 2‐aminoaryl propargyl alcohols successfully underwent a regioselective intramolecular cyclization in the presence of Ca(OTf)2 to give 2,4‐disubstituted quinolines. Cross‐coupling reactions of the iodoquinolines were also performed without any effect to the diazo functionality.