Total synthesis of ochnaflavone

• Monica M. Ndoile and
• Fanie R. van Heerden

Beilstein J. Org. Chem. 2013, 9, 1346–1351, doi:10.3762/bjoc.9.152

• Monica M. Ndoile Fanie R. van Heerden School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X01, Scottsville 3209, Pietermaritzburg, South Africa 10.3762/bjoc.9.152 Abstract The first total syntheses of ochnaflavone, an asymmetric biflavone consisting of apigenin and luteolin

• moieties, and the permethyl ether of 2,3,2'',3''-tetrahydroochnaflavone have been achieved. The key steps in the synthesis of ochnaflavone were the formation of a diaryl ether and ring cyclization of an ether-linked dimeric chalcone to assemble the two flavone nuclei. Optimal experimental conditions for

• the oxidative cyclization to form ochnaflavone were established. Keywords: biflavone; diaryl ether; natural products; nucleophilic aromatic substitution; ochnaflavone; tetrahydroochnaflavone; Introduction Biflavonoids are a class of compounds that are receiving increasing attention because of their