Synthesis and Antirheumatic Activity of the Metabolites of Esonarimod

Highly Enantioselective Dimerization of α,β-Enones Catalyzed by a Rigid Quaternary Ammonium Salt

“…The products of this dimerization are useful intermediates for the syntheses of chiral γ-keto acids, important chiral backbones for the preparation of peptide mimetics (peptide isosteres) in drug discovery, such as, human neutrophile elastase inhibitors 11 and angiotensin converting enzyme inhibitors . Preparation of chiral γ-keto acids was previously problematic. − To our knowledge, no catalytic asymmetric route to these compounds has been reported previously. The chiral γ-keto acids 9 and 10 were easily synthesized by ozonolysis of 4 and 7d at −78 °C in ethyl acetate, followed by oxidation with hydrogen peroxide at ambient temperature in 90% yield (Scheme ).…”