A series of fluorinated flavanones were synthesized in moderate to good yields with excellent diastereoselectivities under mild reaction conditions via a one-pot tandem procedure involving a proline-catalyzed Knoevenagel condensation, a Michael addition, and an electrophilic fluorination by NFSI.
Asymmetric Synthesis of Fluorinated Flavanone Derivatives by an Organocatalytic Tandem Intramolecular Oxa-Michael Addition/Electrophilic Fluorination Reaction by Using Bifunctional Cinchona Alkaloids
A bifunctional quinidine derivative, containing a trifluoromethyl group, was found to catalyze a tandem intramolecular oxa‐Michael addition/electrophilic fluorination reaction of activated α,β‐unsaturated ketones (see scheme). A series of chiral fluorinated flavanone derivatives were obtained in excellent yields and with high enantioselectivities.