The Synthesis of Stypandrol, a Toxic Binaphthalenetetrol Isolated From Stypandra imbricata : New Syntheses of Dianellidin and Stypandrone

Abstract

New syntheses of the naphthalenoid natural products dianellidin [1- (1,8-dihydroxy-3-methylnaphthalen-2-yl) ethanone ] (2) and stypandrone [6-acetyl-5-hydroxy-7-methylnaphthalenel-1,4-dione] (20), which rely on the Fries rearrangement, are described. This methodology is then applied to the synthesis of stypandrol [1,1′-(1,1′,8,8′-tetrahydroxy- 6,6′-dimethyl-2,2′-binaphthalene-7,7′-diyl) bisethanone ] (1), a toxic naphthalenetetrol isolated from Stypandra imbricata R.Br. ('blind grass').