Highly enantioselective carbene insertion into N-H bonds of aliphatic amines

Aliphatic amines strongly coordinate, and therefore easily inhibit, the activity of transition-metal catalysts, posing a marked challenge to nitrogen-hydrogen (N–H) insertion reactions. Here, we report highly enantioselective carbene insertion into N–H bonds of aliphatic amines using two catalysts in tandem: an achiral copper complex and chiral amino-thiourea. Coordination by a homoscorpionate ligand protects the copper center that activates the carbene precursor. The chiral amino-thiourea catalyst then promotes enantioselective proton transfer to generate the stereocenter of the insertion product. This reaction couples a wide variety of diazo esters and amines to produce chiral α-alkyl α–amino acid derivatives.

Source: ScienceNOW - November 20, 2019 Category: Science Authors: Li, M.-L., Yu, J.-H., Li, Y.-H., Zhu, S.-F., Zhou, Q.-L. Tags: Chemistry reports Source Type: news