The present invention provides an intermediate compound used for synthesis of polyene chain structure, that is an important moiety of carotenoid compounds, a process for preparing the same, and carotenoid polyene chain compounds prepared by using the intermediate, and, in particular, a process for preparing lycopene. The process for preparing the carotenoid polyene chain compound employs an allylic sulfone compound as starting material, which is reacted with C-5 sulfide compound to extend the carbon chain. The resultant thio-sulfone compound is oxidized, and the obtained disulfone compound is combined with C-10 di(haloallylic) sulfide compound to form a chain compound containing the desired number of carbon atoms. Then, the diallylic sulfone obtained by oxidation of the diallylic sulfide is subjected to Ramberg-Baklund reaction in order to form the central triene bond. After removal of sulfonyl groups, carotenoid polyene chain compound is obtained.
