Copper‐Catalyzed Enantioconvergent Radical C(sp<sup>3</sup>)−N Cross‐Coupling: Access to α,α‐Disubstituted Amino Acids
Yu‐Feng Zhang, Jiahuan Wang, Ning‐Yuan Yang, Zheng Chen, Li‐Lei Wang, Qiang‐Shuai Gu, Zhong‐Liang Li, Xin‐Yuan Liu
Abstract
Transition-metal catalyzed enantioconvergent cross-coupling of tertiary alkyl halides with ammonia offers a rapid avenue to chiral unnatural α,α-disubstituted amino acids. However, the construction of chiral C-N bonds between tertiary-carbon electrophiles and nitrogen nucleophiles presented a great challenge owing to steric congestion. We report a copper-catalyzed enantioconvergent radical C-N cross-coupling of alkyl halides with sulfoximines (as ammonia surrogates) under mild conditions by employing a chiral anionic N,N,N-ligand with a long spreading side arm. An array of α,α-disubstituted amino acid derivatives were obtained with good efficiency and enantioselectivity. The synthetic utility of the strategy has been showcased by the elaboration of the coupling products into different chiral α-fully substituted amine building blocks.