Synthesis of Carotenoids in the Gliding Bacteria Taxeobacter: (all-E,2′R)-3-Deoxy-2′-hydroxyflexixanthin

Article abstract of DOI:10.1002/hlca.19970800317

The C₄₀-carotenoid (all-E,2′,R)-deoxy-2′-hydroxyflexixanthin (= 1′,2′-dihydroxy-3′,4′-didehydro-1′,2′- dihydro-β,ψ-caroten-4-one; (2′R)-2) was synthesized according to a C₁₅ + C₁₀ + C₅ + C₁₀ = C₄₀ strategy. The chiral centre was introduced into the C₁₀-end group by the enantioselective Sharpless dihydroxylation. The four building blocks were coupled by applying four consecutive Wittig reactions. By comparison of the CD spectra of the synthetic (2′R)-2 with those of 2 isolated from the gliding bacteria Taxeobacter, the configuration of natural 2 was determined as (2′R).