Highly enantioselective protonation of prochiral lithium enolates is disclosed. The present method employed (S,R(s)) CF3-hydroxy sulfoxide (3b) as the chiral protonating agent, and the protonation or lithium enolates of cyclohexanone derivatives with 3b proceeded with high enantioselectivities.
Kosugi, H., Hoshino, K., & Uda, H. (1997). Highly enantiofacial protonation of prochiral lithium enolates with chiral β-hydroxy sulfoxides. Tetrahedron Letters, 38(39), 6861–6864. https://doi.org/10.1016/S0040-4039(97)01618-3