Organocatalytic Enantioselective Decarboxylative Protonation Reaction of Meldrum's Acid Derivatives under PTC Conditions
Abstract
An original organocatalyzed enantioselective protonation sequence of a transient quaternary ammonium enolate species has been developed by starting from readily available disubstituted Meldrum's acid derivatives and phenols. Under phase‐transfer‐catalytic (PTC) conditions, chiral nonracemic 2‐aryl propionic ester derivatives were obtained in good isolated yields with enantioselectivities up to 70 % ee. The usefulness of the approach was demonstrated by the synthesis of enantioenriched (S)‐ibuprofen.