Stereoselective Synthesis ofcis-andtrans-3,4-Dihydro-3,4,8-trihydroxynaphthalen-1(2H)-one

A short and efficient protocol for the stereoselective synthesis of racemic trans- and cis-3,4-dihydro3,4,8-trihydroxynaphthalen-1(2H)-one (1 and 2, resp.), is described, comprising nine and eight steps starting from commercial juglone (=5-hydroxynaphthalene-1,4-dione; 12) (Scheme 4). Furthermore, an attempt to obtain 1 and 2 via phthalide annulation as the key step (Schemes 2 and 3) and a regioselective oxidation of the intermediate 1,2,3,4-tetrahydronaphthalene-1,2,4,5-tetrols 27 and 28 with activated MnO(2) were carried out (Scheme 4).