Abstract
The catalytic asymmetric 1,3-dipolar cycloaddition of pyruvate-derived nitrones to α,β-unsaturated aldehydes was investigated in the presence of various chiral amines. Highly functionalized isoxazolidines containing a quaternary stereocenter were obtained in moderate yields with up to 92% ee. To the best of our knowledge, this is the first example of an enantioselective 1,3-dipolar cycloaddition of ketonitrones. The model product was subsequently transformed into a 2-pyrrolidinone derivative in two steps.