Stereocontrolled synthesis of (S)-9-cis-4-oxo-13,14-dihydroretinoic acid

(S)-9-cis-4-Oxo-13,14-dihydroretinoic acid (S)-1, a new major endogenous vitamin A metabolite that activates retinoic acid receptor signaling both in vitro and in vivo, has been synthesized stereoselectively by Horner-Wadsworth-Emmons condensation and Stille cross-coupling as bond forming reactions.