Easy access to both enantiomers of 5-hydroxyequol and 3-(4-hydroxyphenyl)chroman-8-ol

Abstract

5-Hydroxyequol, a biologically active isoflavone metabolite from genistein, has been synthesized enantioselectively from 3-(2,4,6-trimethoxyphenyl)propanal by using MacMillans’ asymmetric α -arylation protocol of carbonyl compound. (S)- and (R)-5-Hydroxyequols have been obtained in 90% and 88% ee, respectively, by employing enantiomeric imidazolidinone catalysts derived from D- and L-phenylglycines. The absolute configuration of natural 5-hydroxyequol has been definitely assigned to (S)-stereochemistry. (S)- And (R)-3-(4-hydroxyphenyl)chroman-8-ol, an unnatural equol isomer, have also been synthesized for the first time in 76% and 84% ee, respectively.

Keywords

• 5-Hydroxyequol
• Asymmetric synthesis
• α-Arylation
• Isoflavone
• MacMillan’s catalyst