Ligand-Enabled Palladium(II)-Catalyzed Enantioselective ß-C(sp3 )-H Arylation of Aliphatic Tertiary Amides.

Amide is one of the most widespread functional groups in organic and bioorganic chemistry, and it would be valuable to achieve stereoselective C(sp3 )-H functionalization in amide molecules. Palladium(II) catalysis has been prevalently used in the C-H activation chemistry in the past decades, however, due to the weakly-coordinating feature of simple amides, it is challenging to achieve their direct C(sp3 )-H functionalization with enantiocontrol by PdII catalysis. Our group has developed sulfoxide-2-hydroxypridine (SOHP) ligands, which exhibited remarkable activity in Pd-catalyzed C(sp2 )-H activation. In this work, we demonstrate that chiral SOHP ligands served as an ideal solution to enantioselective C(sp3 )-H activation in simple amides. Herein, we report an efficient asymmetric PdII /SOHP-catalyzed ß-C(sp3 )-H arylation of aliphatic tertiary amides, in which the SOHP ligand plays a key role in the stereoselective C-H deprotonation-metalation step.