27298-99-3Relevant articles and documents
Chirality switching in the crystallization of 1-(4-chlorophenyl) ethylamine with binaphthoic acid by ketimine formation
Jin, Ying-Ji,Choi, Yunseo,Chen, Qian,Shirbhate, Mukesh Eknath,Huang, Haofei,Kim, Youngmee,Kim, Sung-Jin,Jun, Moo-Jin,Koo, Eon Cheol,Kim, Kwan Mook
, p. 1690 - 1695 (2016)
Axially chiral binaphthoic acid (BNA) was studied as a resolving agent for a stereoselective crystallization of 1-(4-chlorophenyl)ethylamine (CPEA). The diastereomeric pair of (R)-BNA/(S)-CPEA crystallizes in methylene chloride, on the other hand, the pair of (S)-BNA/(S)-CPEA crystallizes in acetone. The switch of the solubility of the diastereomeric pair is due to the imine formation with acetone. The very low solubility of the BNA/imine pair appears to be responsible for the fast and complete imine formation. The crystal structure of the BNA part in both crystals of the diastereomers maintains a same feature. Asymmetric chiral channels and pockets composed by intermolecular packing of BNA molecules appear in the crystal structures, and the robustness of them seem to contribute to the recognition of the chirality of CPEA with high selectivity.
Enzymatic Primary Amination of Benzylic and Allylic C(sp3)-H Bonds
Jia, Zhi-Jun,Gao, Shilong,Arnold, Frances H.
supporting information, p. 10279 - 10283 (2020/07/27)
Aliphatic primary amines are prevalent in natural products, pharmaceuticals, and functional materials. While a plethora of processes are reported for their synthesis, methods that directly install a free amine group into C(sp3)-H bonds remain unprecedented. Here, we report a set of new-to-nature enzymes that catalyze the direct primary amination of C(sp3)-H bonds with excellent chemo-, regio-, and enantioselectivity, using a readily available hydroxylamine derivative as the nitrogen source. Directed evolution of genetically encoded cytochrome P411 enzymes (P450s whose Cys axial ligand to the heme iron has been replaced with Ser) generated variants that selectively functionalize benzylic and allylic C-H bonds, affording a broad scope of enantioenriched primary amines. This biocatalytic process is efficient and selective (up to 3930 TTN and 96percent ee), and can be performed on preparative scale.
Asymmetric Synthesis of Chiral Primary Amines by Ruthenium-Catalyzed Direct Reductive Amination of Alkyl Aryl Ketones with Ammonium Salts and Molecular H2
Tan, Xuefeng,Gao, Shuang,Zeng, Weijun,Xin, Shan,Yin, Qin,Zhang, Xumu
supporting information, p. 2024 - 2027 (2018/02/19)
A ruthenium/C3-TunePhos catalytic system has been identified for highly efficient direct reductive amination of simple ketones. The strategy makes use of ammonium acetate as the amine source and H2 as the reductant and is a user-friendly and operatively simple access to industrially relevant primary amines. Excellent enantiocontrol (>90% ee for most cases) was achieved with a wide range of alkyl aryl ketones. The practicability of this methodology has been highlighted by scalable synthesis of key intermediates of three drug molecules. Moreover, an improved synthetic route to the optimal diphosphine ligand C3-TunePhos is also presented.