N-benzyl aspartate nitrones: unprecedented single-step synthesis and [3 + 2] cycloaddition reactions with alkenes.
N-benzyl aspartate nitrones 2, prepared by addition of N-benzylhydroxylamine to dialkyl acetylenedicarboxylates 1, underwent [3 + 2] thermal cycloaddition with a wide range of alkenes to afford isoxazolidines 4 bearing a polyfunctionalized quaternary center. Under these uncatalyzed conditions, the trans stereocontrol observed with vinyl ethers is higher than that obtained with all acyclic activated nitrones reported to date. The first asymmetric access to a type-4 pure adduct was achieved starting from the chiral aspartate nitrone derived from (S)-alpha-methylbenzylhydroxylamine.
Nguyen
Thanh Binh
TB
UCO2M UMR 6011 & IRIM2F FR 2575 CNRS, Université du Maine, 72085, Le Mans, France.
Martel
Arnaud
A
Dhal
Robert
R
Dujardin
Gilles
G