Biomimetic Approach to the Catalytic Enantioselective Synthesis of Flavonoids

Herein is reported the direct asymmetric
addition of phenol nucleophiles
to benzopyrylium salts as a means to produce enantioenriched flavonoid-like
compounds. This enantioselective C–C bond construction was
achieved through a chiral anion phase-transfer strategy that mimics
the proposed biosynthesis of this structurally diverse set of natural
products. The utility of this methodology was demonstrated in enantioselective
synthesis of a 2,8-dioxabicyclo[3.3.1]­nonane and a 2,4-diarylbenzopyran.