Synthesis of (3S,4R)-3,4-isopropylidenedioxy-1-pyrroline-N-oxide, an enantiopure functionalized cyclic nitrone; cycloaddition reactions with dimethyl maleate and dimethyl fumarate

(3S,4R)-3,4-Isopropylidenedioxy-1-pyrroline-N-oxide [(-)-4] has been prepared in enantiomerically-pure form from D-arabinose, and (+)-4 is similarly accessible from L-arabinose; cycloaddition reactions of (-)-4 with dimethyl maleate and dimethyl fumarate are reported.