Synthesis and Study of Oxadisilole-Fused Benzisoxazoles or Naphthisoxazoles
Oxadisilole-fused benzisoxazoles or naphthisoxazoles were obtained through 1,3-dipolar cycloaddition of arynes with nitrile oxides in good yields at room temperature. Key to the procedure is the simultaneous in situ generation of reactive nitrile oxides from arenecarbohydroximoyl chlorides and aryne reactants from benzobis(oxadisilole) or 2,3-naphthoxadisilole. One oxadisilole-fused benzisoxazole is a new precursor of a benzyne formed by a phenyliodination/fluoride-induced elimination protocol. By using this benzyne, cycloadducts were synthesized in good yields. The de-oxadisilole reaction of some of the oxadisilole-fused benzisoxazoles could be easily conducted with a 1.0 M solution of tetrabutylammonium fluoride in THF at room temperature.