A General Enantioselective C−H Arylation Using an Immobilized Recoverable Palladium Catalyst

Abstract

We herein report a general and efficient enantioselective C–H arylation of aryl bromides based on the use of BozPhos as the bisphosphine ligand and SP‐NHC‐PdII as recoverable heterogeneous catalyst. By exploiting the “release and catch” mechanism of action of the catalytic system, we used BozPhos as a broadly applicable chiral ligand, furnishing high enantioselectivities across all types of examined substrates containing methyl, cyclopropyl and aryl C–H bonds. For each reaction, the reaction scope was investigated, giving rise to 30 enantioenriched products, obtained with high yields and enantioselectivities, and minimal palladium leaching. The developed catalytic system provides a more sustainable solution compared to homogeneous systems for the synthesis of high added‐value chiral products through recycling of the precious metal.

Access to chiral dihydrophenanthridines via a palladium(0)-catalyzed Suzuki coupling and C–H arylation cascade reaction using new chiral-bridged biphenyl bifunctional ligands

“…Consistent with this mechanism, chiral auxiliary ligands and chiral bases have been successfully employed to induce enantioselectivity in palladium(0)-catalyzed C–H activation reactions. 4–7 To our knowledge, a pioneering study by Baudoin and co-workers described the union of an ancillary ligand and the base in the same bifunctional molecule 9 for directing palladium(0)-catalyzed enantioselective C–H arylation, generating bioactive dihydrophenanthridine derivatives. 10 However, heterocyclic aromatic substrates were not studied in this catalytic system and their unsatisfactory enantioselective control in certain substrates still restricts their applications.…”

“… 1 Recent impressive progress in this vibrant and fast advancing research area has opened up unimaginable opportunities for more effective strategic disconnection and streamlined synthesis, 2 and catalytic enantioselective C–H activation has emerged as a simple and powerful method for constructing enantio-enriched molecules of high added value. 3 Palladium(0)-catalyzed asymmetric intramolecular C–H functionalization generates cyclic products that allow access to four-, 4 five-, 5 six-, 6 and seven-membered rings, 7 which typically proceeds via a reversible carboxylate-assisted concerted metallation-deprotonation (CMD) mechanism. 8 The enantio-determining step is usually C–H activation.…”