Synthesis of trihydroxylated pyrrolizidines, the enantiomer of 2-epihyacinthacine A2 and indolizidine analogues of the natural alkaloids is reported. The key step of these syntheses is the stereoselective samarium diodide-induced coupling of the chiral nitrone prepared from d-ribose with methyl acrylate. The nitrone derived from d-ribose possessing C2/C3 syn configuration reacted with methyl acrylate