Synthesis of oxygenated 4-arylisoflavans and 4-arylflavans

Oxygenated 4-arylisoflavans and 4-heteroarylisoflavans were synthesized in good yields via BF3·OEt2 catalyzed arylation reactions of 4′,7-diacetoxyisoflavan-4-ol 8 with activated aryl and heteroaryl compounds. These reactions were found to produce stereoselectively the trans isomers. Similar reactions of 4′,7-diacetoxyflavan-4-ol 16 afforded the corresponding 4-arylflavans and 4-heteroarylflavans as mixtures of cis/trans isomers.