The novel intermediate compound which can be efficiently utilized in the synthesis of carotenoid compounds based on the sulfone chemistry, the preparation method of the same, and the practical synthetic process for preparing .beta.-carotene by the use of the above novel compound are disclosed. The synthesis of .beta.-carotene is characterized by the double elimination reactions of the C.sub.40 compound containing both the benzenesulfonyl group and the group X (either halogen or ether), which can...