Synthesis of (all-E,2R,2′R)-oscillol

Optically active (all-E,2R,2′R)-oscillol (= (all-E,2R,2′R)-3,4,3′,4′-tetradehydro-1,2,1′,2′-tetrahydro-ψ,ψ-carotene-1,2,1′,2′-tetrol; 1 ) was synthesized according to the C₁₀ + C₂₀ + C₁₀ = C₄₀ strategy, applying the Wittig reaction to couple the synthons 4 and 6 . The chiral centre was introduced by a Sharpless dihydroxylation of 3-methylbut-2-enyl 4-nitrobenzoate ( 8 ).