A simple conversion of 2-methoxynaphthoquinones to 2,3,4,5-tetrahydronaphtho[1,2-b]furan-4,5-diones. Application to the synthesis of (.+-.)-trypethelones
The fungus Verticilliumlamellicola affords lamellicolicanhydride 1 (5 - methyl - 2,4.7 - trihydroxy -1,8 - naphthalicanhydride) together with small amounts of the quinone 2, the carbonate 3 and the chloro compound 4. Selective reactions of the functional groups in these and their derivatives have been used to interrelate these and effect conversion of 1 into 18, the anhydride obtained from Penicillium