<i>m</i>CPBA-Mediated Intramolecular Oxidative Annulation of <i>ortho</i>-Crotyl or Cinnamyl Arylaldehydes: Synthesis of Benzofused Five‑, Six‑, and Seven-Membered Oxacycles

<i>m</i>CPBA-mediated intramolecular oxidative annulation of <i>ortho</i>-crotyl or cinnamyl arylaldehydes provides chroman, coumaran, isochroman, and tetrahydrobenzo­[<i>c</i>]­oxepine under different reaction conditions. This research investigates the reaction conditions for facile and efficient transformation.