A new approach to 3-hydroxyprolinol derivatives by samarium diiodide-mediated reductive coupling of chiral nitrone with carbonyl compounds.

A flexible diastereoselective approach to trans-(3S)-hydroxyprolinol derivatives is described, which is based on the samarium diiodide-mediated reductive coupling of the chiral 1-pyrroline N-oxide (nitrone)(S)-10 with carbonyl compounds. The reductive hydroxyalkylation of nitrone 10 with ketones and aromatic aldehydes is highly diastereoselective in establishing the C-2 chiral center of the pyrrolidine ring.