206060-40-4Relevant articles and documents
Ligand-enabled β-C-H arylation of α-amino acids using a simple and practical auxiliary
Chen, Gang,Shigenari, Toshihiko,Jain, Pankaj,Zhang, Zhipeng,Jin, Zhong,He, Jian,Li, Suhua,Mapelli, Claudio,Miller, Michael M.,Poss, Michael A.,Scola, Paul M.,Yeung, Kap-Sun,Yu, Jin-Quan
supporting information, p. 3338 - 3351 (2015/03/30)
Pd-catalyzed β-C-H functionalizations of carboxylic acid derivatives using an auxiliary as a directing group have been extensively explored in the past decade. In comparison to the most widely used auxiliaries in asymmetric synthesis, the simplicity and practicality of the auxiliaries developed for C-H activation remains to be improved. We previously developed a simple N-methoxyamide auxiliary to direct β-C-H activation, albeit this system was not compatible with carboxylic acids containing α-hydrogen atoms. Herein we report the development of a pyridine-type ligand that overcomes this limitation of the N-methoxyamide auxiliary, leading to a significant improvement of β-arylation of carboxylic acid derivatives, especially α-amino acids. The arylation using this practical auxiliary is applied to the gram-scale syntheses of unnatural amino acids, bioactive molecules, and chiral bis(oxazoline) ligands.