ONE-POT THREE-COMPONENT SYNTHESIS OF 3,5-DISUBSTITUTED ISOXAZOLES BY A COUPLING-CYCLOCONDENSATION SEQUENCE

摘要

A convenient one-pot procedure for the synthesis of 3,5-disubstituted isoxazoles from acid chloride, terminal alkyne, and hydroxylamine hydrochloride catalyzed by Pd(PPh3)2Cl2/CuI has been developed. The coupling of acid chlorides to terminal alkynes afforded α,β-unsaturated ynones that underwent in situ cyclocondensation with hydroxylamines to afford the desired isoxazoles in 44-76% isolated yields.