Biomimetic Synthesis of Podophyllum Lignans

Abstract

(±)-lsopodophyllotoxone 6a and the related lactones 8a and 9a were synthesized by a biomimetic procedure from the ester 5a by oxidation with a CrO₃-HBF₄-MeCN reagent system in one step. 4'-Benzyl-isopodophyllotoxone 6b, 4'-benzyl-picropodophyllone 7b, and the γ-lactones 8b and 9b were also synthesized from the ester 5b by oxidation with the same reagent system.