STEREOSELECTIVE SYNTHESIS OF THE BRASSINOLIDE SIDE CHAIN: NOVEL SYNTHESIS OF BRASSINOLIDE AND RELATED COMPOUNDS

Article abstract of DOI:10.1016/S0040-4020(01)85457-0

A stereoselective synthesis of the brassinolide side chain involves the lactonization of Z-10 under acidic condition to give an α,β-unsaturated-δ-lactone 11 with the inversion of the configuration at C-22 of the epoxy steroid in quantitative yield.The 22R,23R,24R-γ-hydroxy-δ-lactone 14 was used as key intermediate for the syntheses of brassinolide (1), homobrassinolide (2), and typhasterol (4) as well as the side chain of the dolicholide (3).