REGIO- AND STEREOSELECTIVE OXYGENATION OF FLAVAN-3-OL-, 4-ARYLFLAVAN-3-OL-, AND BIFLAVANOID-DERIVATIVES WITH POTASSIUM PERSULPHATE

Article abstract of DOI:10.1016/S0040-4020(01)87876-5

The phenolic methyl ethers of flavan-3-ols, 4-arylflavan-3-ols, and (-)-fisetinidol-(4,8)-(+)-catechin biflavanoids are susceptible to regio- and stereoselective hydroxylation at C-4 in moderate to high yields with potassium persulphate/cupric sulphate in aqueous acetonitrile.The resultant 4-functionalized analogues are of both synthetic and degradative significance in condensed tannin chemistry.