One-pot synthesis of 1H-isochromenes and 1,2-dihydroisoquinolines by a sequential isocyanide-based multicomponent/Wittig reaction

A one-pot synthesis of 1H-isochromenes and 1,2-dihydroisoquinolines by a I-MCR/Wittig sequence was developed. The reaction of phosphonium salt 5, an acid, an amine ( or without), and an isocyanide gave the 1H-isochromenes 7 or 1,2-dihydroisoquinolines 9 in good yields by a sequential Passerini or Ugi condensation and an intramolecular Wittig reaction in the presence of K2CO3.