Highly Enantioselective Insertion of Carbenoids into O−H Bonds of Phenols: An Efficient Approach to Chiral α-Aryloxycarboxylic Esters

A highly efficient copper-catalyzed asymmetric carbenoid insertion into O−H bonds of phenols has been realized by using chiral spiro bisoxazoline ligands, affording α-aryloxypropionates and the related propionic acids in high yields with excellent enantiomeric excesses.