A mild catalytic procedure for the efficient oxidative cyclization of aldoximes with maleimides mediated by hypervalent iodine(III) active species has been developed. This catalytic cyclization affords the corresponding pyrrolo-isoxazole products in generally good yields. The catalytic cycle involves active hydroxy(aryl)iodonium species generated in situ from 2-iodobenzoic acid as precatalyst and m-chloroperoxybenzoic acid (m-CPBA) as terminal oxidant in the presence of trifluoromethanesulfonic acid. The presence of active hydroxy(aryl)iodonium species in this reaction has been confirmed by ESI-mass spectrometry and1H NMR spectroscopy. (Figure presented.) .
Bibliographical noteFunding Information:
This work was supported by research grants from the National Science Foundation (CHE-1262479), Russian Science Foundation (RSF-16-13-10081), and by the Asahi Glass Foundation.
- iodonium species