Isoflavones are synthesized in an one-pot reaction by treating the hypervalent iodine(III) reagent, [hydroxy(tosyloxy)iodo]benzene (HTIB, Koser's reagent) with 2'-benzoyloxychalcones in McOH. A combined use of (diacetoxyiodo)benzene (DIB)/p-toluenesulfonic acid (TsOH) is also effective for the same purpose. As an extension of these monomeric reagents, polymer-supported DIB PSDIB, poly[4-(diacetoxy)iodo]styrene}
We have developed a regioselective synthesis of 3,4-disubstituted isoxazoles by using a chalcone-rearrangement strategy. The reaction of β-ketoacetals with hydroxylamine hydrochloride and pyridine afforded the corresponding 3,4-disubstituted isoxazoles via isoxazolines or oximes. Depending on the substrate, another disubstituted isomer was also obtained under our optimized conditions, and a reaction