To obtain a zeaxanthin in high yield from a readily available trimethylcyclohexanone through few reaction processes via an important intermediate.

This zeaxanthin is obtained through the following process: (4R)-4-hydroxy-2,2,6-trimethylcyclohexanone of formula I is reacted with dichloromethyllithium, the reaction mixture is heated to form a bicyclic 10C- aldehyde of formula II, which is then reacted with acetone or the like to form a bicyclic 13C-ketone, which, in turn, is converted to a 15C-carbinol of formula III; the carbinol is then reacted with a triarylphosphine to form a mixture of a 15C triarylphosphonium salt of formula IV and an iso-isomer (Ar is an aryl; X is one equivalent anion of an strong acid), and in each case, about 2 mol of the above reaction mixture formed is subjected to double Wittig reaction with 2,7-dimethyl-2,4,6-octatrienedial of formula V to effect conversion to the objective (3R,3'R)-zeaxanthin of formula VI.