Intramolecular [3+2] nitrone-alkyne cycloaddition

Abstract

It is demonstrated that the [3+2] cycloaddition of a nitrone to an alkyne is facile when the length of the tether connecting the two reacting sites is appropriate. The resulting [3+2] cycloaddition products, isoxazolidines can be further converted to 3-hydroxy-3-pyrrolin-2-ones and alpha-keto-beta, gamma-unsaturated esters by reductive and oxidative cleavage, respectively.