Total synthesis of paracentrone, C31-allenic apo-carotenoid

Abstract

The stereocontrolled total synthesis of a C₃₁-allenic apo-carotenoid, paracentrone, was achieved by the convergent C₂₀ + C₁₁ = C₃₁ strategy. The key elements of our synthesis were the Pd-catalyzed cross-coupling to stereoselectively construct the conjugated polyene backbone skeleton and the designed geometrical isomerization at the central double bond of the conjugated polyene chain. In addition, the terminal oxygenated cyclohexane ring having the allenic moiety was prepared by the highly diastereoselective Sharpless epoxidation under our own reaction conditions.