Enantioselective Reduction of Biaryl Lactones via DKR

Significance

Chiral biaryl compounds are typically accessed by biaryl couplings followed by a resolution; a challenging approach in cases of hindered ortho-substituted aryl partners. The above strategy is advantageous since the biaryl coupling is effected on intramolecular aryl partners tethered by an ester function. The racemic atropisomer mixture is submitted to a dynamic kinetic resolution (DKR) where asymmetric reduction occurs at a temperature where rapid isomerization of the
atropisomers can take place. Reduction of the matched atropisomer fully converts the racemic mixture into the desired enantiomer of the biaryl compound in high enantiomeric ecxess.