Chiral 3-hydroxypyrrolidin-2-ones from a Baylis–Hillman adduct: convergent, stereoselective synthesis of a glycosidase inhibitor

The O-silyl derivative 4b, prepared starting from the Baylis–Hillman adduct 4a, underwent cyclization on treatment with (S)-phenylethylamine, to give to an equimolar mixture of the 4,5-cis-disubstituted pyrrolidin-2-ones 9 and 10, exclusively, which after separation by silica gel chromatography were both converted into the 3-hydroxy-4-hydroxymethylpyrrolidine 1 a glycosidase inhibitor.