Experimental and Theoretical Evidence for Relativistic Catalytic Activity in C-H Activation of N-Phenylbenzamide Using a Cationic Iridium Complex.

This study elucidates that relativistic effect plays a key role in catalytic C-H activation using a cationic Ir complex. Experiments show that the cationic Ir(I)-diphosphine catalyst can be used for the deuterium substitution of N-phenylbenzamide, whereas a cationic Rh(I)-diphosphine catalyst is scarcely effective. Density functional theory calculations, including the relativistic effect, demonstrate a large difference in the reaction energy diagrams for the C-H activation of N-phenylbenzamide between the cationic Ir and Rh catalysts. In particular, the relatively low reaction barrier and considerably stabilized product obtained for the Ir catalysts are rationalized by strong Ir-C and Ir-H interactions, which originate from the relativistic self-consistent d-orbital expansion of Ir.

Enantioselective Formal C-H Conjugate Addition of Acetanilides to ß-Substituted Acrylates by Chiral Iridium Catalysts.

The Ir-catalyzed enantioselective reaction of substituted acetanilides with ß-substituted α,ß-unsaturated esters provided chiral 3,3-disubstituted propanoates in high yield with good-to-excellent enantiomeric excess (up to 99 % ee). This transformation, initiated by sp2 C-H bond activation, is the first example of enantioselective formal C-H conjugate addition to ß-substituted α,ß-unsaturated carbonyl compounds. The starting materials are commercially available and/or readily accessible.