Addition of aldehydes to the new enantiomerically pure lithiated sulfoxide 4 yielded gamma-butenolides of high enantiomeric purities after elimination of phenylsulfinic acid. The reaction with ketones was less stereoselective. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.
Renard, M. E., & Ghosez, L. (1999). A convergent asymmetric synthesis of gamma-butenolides. Tetrahedron Letters, 40(34), 6237-6240. https://doi.org/10.1016/S0040-4039(99)01242-3 (Original work published 1999)