2,1‐Benzisoxazoles

Synthesis of 2,1-benzisoxazole-3(1H)-ones by base-mediated photochemical N–O bond-forming cyclization of 2-azidobenzoic acids

“…Possibly, similar to the benzofuroxan and 3-amino-6-nitro-2,1-benzisoxazole formation, the carboxylate group of A (Lewis base) donates an electron lone pair to the electron-deficient singlet nitrene fragment of A (Lewis acid) with formation of the N–O bond in 2 through a 1,5-electrocyclization reaction [ 56 – 57 ].…”