A Sequential One‐Pot Synthesis of Quinoline‐Fused Benzoxe(Aze)pines via Intramolecular Reductive Heck Cyclisation

ABSTRACT A new heterocyclic fused quinoline system namely quinoline fused benzoxepines were obtained in a straight forward sequential one‐pot synthesis. The synthetic route includes O ‐alkylation of 2‐(phenyl ethynyl) phenol with 2‐chloro‐3‐(chloromethyl) quinolines and a subsequent intramolecular reductive Heck cyclization. The stereochemistry of the exocyclic double bond at C‐6 in target benzoxepines is confirmed as ( E )‐configuration from single crystal X‐ray diffraction. The synthesis is widened to benzazepine analogues by replacing 2‐(phenyl ethynyl) phenol with that of N ‐tosyl/mesyl‐2‐(phenylethynyl) aniline that is N ‐alkylation and then cyclisation. Highlights of the devised synthetic plan include readily accessible precursors, easy procedures with wide substrate scope and good yields.