转自：康龙化成

Asymmetric Hydrogenation of Ketimines with Minimally Different Alkyl Groups with Minimally Different Alkyl Groups

Mingyang Wang, Shihan Liu, Hao Liu, Yujie Wang, Yu Lan* & Qiang Liu*

Center of Basic Molecular Science (CBMS), Department of Chemistry, Tsinghua University, Beijing, China

College of Chemistry, PingyuanLaboratory, Zhengzhou University, Zhengzhou, Henan, China

—Nature, 2024, 631, 556-562.

Recommended by Shi Li_MOC

KEYWORDS: Asymmetric synthesis,hydrogenation, Mn catalysis (反应类型), C(sp3)–N(sp3) (成键类型),dialkyl ketimines(原料), chiral amine (产物), NNP pincer ligand (其他)

ABSTRACT: Yu Lan and Qiang Liu et al introduce a class of earth-abundant manganese catalysts for the asymmetric hydrogenation of dialkyl ketimines to give a range of chiral amine products. These catalysts distinguish between pairs of minimally differentiated alkyl groups bound to the ketimine, such as methyl and ethyl, and even subtler distinctions, such as ethyl and n-propyl. The degree of enantioselectivity can be adjusted by modifying the components of the chiral manganese catalyst. This reaction demonstrates a wide substrate scope and achieves a turnover number of up to 107,800. The mechanistic studies indicate that exceptional stereoselectivity arises from the modular assembly of confined chiral catalysts and cooperative non-covalent interactions between the catalyst and the substrate.

Background and this work: The distinction between two minimally differentiated alkyl groups

Optimization of reaction parameters

Synthetic scope (selected)

Asymmetric catalysis enables the synthesis of optically active compounds, often requiring the differentiation between two substituents on prochiral substrates. Despite decades of development of mainly noble metal catalysts, achieving differentiation between substituents with similar steric and electronic properties remains a notable challenge. Yu Lanand Qiang Liu et al introduce a class of confined, modularly assembled anionic manganese hydride catalysts, which enable the enantioselective hydrogenation of dialkyl ketimines with a wide substrate scope and a high turnover number.The mechanistic studies indicate that exceptional stereoselectivity arises from the modular assembly of confined chiral catalysts and cooperative non-covalent interactions between the catalyst and the substrate.

（转自：康龙化成）