Synthesis of (4S)-hydroxymethyl-(2R)-(2-propyl)-butyrolactone: A quest for a practical route to an important hydroxyethylene isostere chiron

Several approaches for the stereocontrolled introduction of a 2-propyl group into (4S)-hydroxymethyl-1,4-butyrolactonevia enolate chemistry were investigated. A practical synthesis of the (2R)- and (2S)-isomers was developed.