A new nitrone from C2 symmetric piperidine for the synthesis of hydroxylated indolizidinone

The oxidation of a C2 symmetric piperidine, obtained through a ring enlargement process of the enantiopure protected (4R)-hydroxy-(2S)-hydroxymethyl pyrrolidine, is reported. Oxidation with C-phenyl-N-phenylsulfonyloxaziridine afforded the corresponding nitrone that is too unstable for isolation and which reacted in situ with dimethyl maleate. The major adduct was transformed to the corresponding protected dihydroxyindolizidinone.