An asymmetric, SmI2-mediated approach to γ-butyrolactones using a new, fluorous-tagged auxiliary

A new, fluorous-tagged chiral auxiliary has been developed for the asymmetric, SmI 2 -mediated coupling of aldehydes and α,β-unsaturated esters. γ-Butyrolactones are obtained in moderate to good isolated yield and in high enantiomeric excess. The fluorous tag allows the auxiliary to be conveniently recovered by fluorous solid-phase extraction (FSPE) and reused.