Patent attributes
The preparation of C-3 coupled biflavonoids and C-3 coupled biflavonoid analogs occurs from flavan-3-ones that are contacted with a compound having a nucleophilic aromatic moiety, in the presence of a Lewis acid where an intermediate compound is formed with a C-3 hydroxy group. A flavan-3-ol can be converted to a flavan-3-one as required. The intermediate compound is dehydrated to a flavene with a C-3-C-4 double bond. The flavene compound undergoes hydroboration-oxidation hydration to introduce a C-4 hydroxy group that can be oxidized to an oxo group or can be dihydroxylation to introduce hydroxy groups at the C-4 and C-3 carbons and dehydrated to a biflavonoid or biflavonoid analog having an oxo group at its C-4 carbon and substituted by the selected nucleophilic aromatic moiety on its C-3 carbon.
