STUDIES ON THE CONSTITUENTS OF THE SEEDS OF HERNANDIA OVIGERA L. VIII, SYNTHESES OF ()-DESOXYPODOPHYLLOTOXIN AND ()-BETA -PELTATIN-A METHYL ETHER

(±)-Desoxypodophyllotoxin (2), a chief component of the seeds of Hernandia ovigera L., and (±)-β-peltatin-A methyl ether (3), and analogous phenyltetralin lignan, which have 2,3-trans, 3,4-cis configuration were synthesized according to the method developed for the synthesis of hernandin (1). The syntheses were pursued using the corresponding 4-phenyl-1,2-dihydronaphthalene lactones (9 and 10) followed by cleavage of the lactone moiety to give the unsaturated hydroxy acids (11 and 12). Subsequent hydrogenation and ring closure by means of p-toluenesulfonic acid afforded both 2,3-trans, 3,4-cis, and 2,3-cis lignans (2 and 13 or 3 and 14), which were isolated by preparative thin layer chromatography