We extended actinomycin D as a practical CSA for rapid enantiomeric determination of chiral carboxylic acids by1H NMR spectroscopy.

We developed a copper-catalyzed three component reaction of aryl acetylene, enaminone and sulfonyl azide to construct iminolactone via copper-catalyzed alkyne–azide cycloaddition (CuAAC), Michael addition of metalated ketenimine followed by elimination and 6π electrocyclization.

Herein, we describe two practical methods to synthesize β,γ-unsaturated α-keto esters directly from aldehydes and pyruvates promoted by BF3•Et2O in the presence of Ac2O or by Ti(OEt)4 under mild conditions. A variety of aromatic aldehydes was tolerated to afford the desired products in moderate to excellent yield. Moreover, aliphatic aldehydes and Isatin were also employed to give the γ-alkyl β,γ-unsaturated α-keto esters in moderate yield with use of the Ti(OEt)4 system.

Correction for ‘Enantiomeric NMR discrimination of carboxylic acids using actinomycin D as a chiral solvating agent’ by Liwen Bai, et al., Org. Biomol. Chem., 2019, 17, 1466–1470.