Stereoselective synthesis of cis- or trans-2,4-disubstituted butyrolactones from Wynberg lactone

(R)-Wynberg lactone was used to prepare various asymmetric 2,4-disubstituted butyrolactones in three to four steps. Attainment of any possible stereoisomer, based upon commencement from (R)- or (S)-4-trichloromethyl-2-oxetanone, and the capacity to install disparate substituents at C2 make this approach particularly versatile.