Abstract: Acetylenic RAs is a kind of important drug for treating cancer. In this paper, a novel acetylenic retinoids was synthesized and a directly copper-free Sonogashira coupling between iodoaryl acid and phenylacetylene was developed. In the absence of Cu(Ⅰ), the catalytic coupling of haloaryl carboxylic acids or unactivated aryl bromides with terminal alkynes were shown to occur in the presence of 10 multiple piperidine at 85 ℃ within 20 min with PdCl₂(PPh₃)₂ as catalyst in good yields. The overall yield was 72%. Due to the fact that the reaction is simple and the yield is high, it is applicable to synthesis of other acetylenic RAs.

Key words: Acetylenic retinoids, Sonogashira reaction, PdCl₂(PPh₃)₂ catalyst