An Efficient Approach to the Synthesis of 4H-1-Benzothiopyran-4-ones via Intramolecular Wittig Reaction

Article abstract of DOI:10.1039/c39920001580

The reaction of S-acyl(aroyl)thiosalicylic acids 2 with N-phenyl(triphenylphosphoranylidene)ethenimine 3 in stepwise fashion leads to the acylphosphoranes 5 which subsequently undergo intramolecular Wittig cyclization on the thiolester carbonyl to afford