N-substituted hydroxysuccinimides from (s)-malic acid as new reagents for asymmetric diels-alder additions to enoates

Abstract (S)-N-Methyl-2-hydroxysuccinimide, easily available from natural (S)-malic acid, supplements the previously introduced (R)-pantolactone as chiral auxiliary for asymmetric Diels-Alder reactions of enoates, but yields products of opposite configuration. Practical large-scale preparations of enantiomer pairs of synthetically important Diels-Alder adducts, including adducts from crotonates, are described.