Solution- and solid-phase asymmetric synthesis of substituted N-hydroxypyrrolidine dicarboxylic acids

Nitrone ylids prepared from α-amino aldehyde derivatives undergo 1,3-dipolar cyclocondensation reactions to give enantiopure C-4 branched N-hydroxy proline esters. The different functional groups can be manipulated to provide diversely substituted N-hydroxypyrrolidine dicarboxylic acids. The reaction can be adapted to solid-phase synthesis.