Ylide von Heterocyclen, V [1]. I-, N-und S-Ylide des 2-Pyrons und 2-Pyridons / Ylides of Heterocycles, V [1]. I-, N-and S-Ylides of 2-Pvrones and 2-Pyridones

Abstract

The reaction of the pyrone 1 a or the pyridones 1 b, c with iodosobenzene leads to the iodonium-ylides 2 which undergo thermal rearrangement to the 4-phenyloxy-3-iodo compounds 3. Reductive deiodination of 3 gives the 4-phenyloxy compounds 4. By acid catalyzed treatment with nucleophiles (such as pyridine, nicotinamide, isoquinoline and thiophane) the iodonium-ylides 2 can be converted into the corresponding N- and S-ylides 5. Reaction of 2 with concentrated HCl or HBr gives the 3-halogeno substituted compounds 6.