Synthetic approach to flavanones and flavonesvialigand-free palladium(ii)-catalyzed conjugate addition of arylboronic acids to chromones

Abstract

The remarkable catalytic effects of Fe(OTf)₃ in the context of the Pd(II)-catalyzed conjugate addition of arylboronic acids to chromones were observed to yield a variety of flavanones under mild conditions. The addition of catalytic amounts of DDQ and KNO₂ to the reactions exclusively yielded flavone analogs. The reaction scope for the transformation was fairly broad, affording good yields of a wide range of flavanones and flavones, which are privileged structures in many biologically active compounds.