| Abstract: | The synthesis of a novel rotenone-like molecule, 9-methoxy-8-methyl-6,6a,12,12a-tetrahydro1]benzopyrano-3,4-b]1]benzopyran-12-one ( 2 ) is described. Efficient syntheses of 3,4-dihydro-2H-1]benzopyran-3-one ( 9 ) from ethyl 3-hydroxy-2H-1]benzopyran-4-carboxylate ( 6 ), an intermediate in the synthesis of 2 , were developed. Thermolysis of 6 and 9 in decalin yielded 6,8-dihydro-14H-bis1]benzopyrano3,4-b:4′,3′-e]pyran-14-one ( 8 ), which has previously been described. Also produced in the thermolysis was the isomeric 1H-bis1]-benzopyrano3,4-b:3′,4′-á]pyran-7-(9H)one ( 10 ), the first member of a novel, pentacyclic ring system. |
