Chiral Bifunctional Phosphine-Carboxylate Ligands for Palladium(0)-Catalyzed Enantioselective C−H Arylation
作者:Lei Yang、Markus Neuburger、Olivier Baudoin
DOI:10.1002/anie.201712061
日期:2018.1.26
Previous enantioselective Pd0‐catalyzed C−H activation reactions proceeding via the concerted metalation‐deprotonation mechanism employed either a chiral ancillary ligand, a chiral base, or a bimolecular mixture thereof. This study describes the development of new chiral bifunctional ligands based on a binaphthyl scaffold which incorporates both a phosphine and a carboxylic acid moiety. The optimal
β‐hydrogen atom has been observed in the Pd‐catalyzed homocoupling reactions of o‐bromobenzylamines, providing an expeditious synthetic route to 5,6‐dihydrophenanthridine derivatives. Furthermore, a highly enantioselective synthesis of 6‐aryl‐substituted 5,6‐dihydrophenanthridines was achieved in a one‐pot manner by taking advantage of Rh and Pd catalysis.