Synthesis of (3R,3′R)-Zeaxanthin and Its meso-Stereoisomer from (3R,3′R,6′R)-Lutein via (3R)-3′,4′-Anhydrolutein

A process has been developed for the partial synthesis of (3R,3'R)-zeaxanthin and (3R,3'S; meso)-zeaxanthin from commercially available (3R,3'R,6'R)-lutein. This involves the regioselective hydroboration of a dehydration product of lutein, namely (3R)-3',4'-didehydro-beta, beta-caroten-3-ol [(3R)-3',4'-anhydrolutein], to yield a mixture of (3R,3'R)-zeaxanthin and (3R,3'S; meso)-zeaxanthin followed by separation of these carotenoids by enzyme-mediated acylation. (3R,3'R,6'R)-Lutein, (3R,3'R)-zeaxanthin and its mesoisomer accumulate in human ocular tissues and have been implicated in the prevention of age-related macular degeneration (AMD).