Synthesis of 3,4-disubsituted isoxazoles via enamine [3+2] cycloaddition

Abstract

Enamine-triggered [3+2]-cycloaddition reactions of aldehydes and N-hydroximidoyl chlorides in the presence of triethylamine give rise to 3,4-disubstituted isoxazoles upon oxidation of the cycloadduct 3,4,5-trisubstituted 5-(pyrrolidinyl)-4,5-dihydroisoxazoles. This offers a high yielding, regiospecific and metal-free synthetic route for the synthesis of 3,4-disubstituted isoxazoles. © Georg Thieme Verlag Stuttgart · New York.