Total Synthesis of the Potent Anticancer Aglaia Metabolites (-)-Silvestrol and (-)-Episilvestrol and the Active Analogue (-)-4-Desmethoxyepisilvestrol

Abstract

Total synthesis of the anticancer 1,4-dioxane containing natural products silvestrol (1) and episilvestrol (2) is described by an approach based on the proposed biosynthesis of these novel compounds. The key steps included an oxidative rearrangement of the protected D-glucose derivative 11 to afford the 1,4-dioxane 12, which could be elaborated to the coupling partner 5 and a photochemical [3 + 2] cycloadditon between the 3-hydroxyflavone 27 and methyl cinnamate followed by base-induced α-ketol rearrangement and reduction to give the cyclopentabenzofuran core 33. The core (-)-6 and 1,4-dioxane fragment 5 were united by a highly stereoselective Mitsunobu coupling with the modified azodicarbox..