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1. Traceless Redox-Annulations of Alicyclic Amines

   https://doi.org/10.1055/s-0040-1706004  

   Rickertsen, Dillon R. ; Ma, Longle ; Paul, Anirudra ; Abboud, Khalil A. ; Seidel, Daniel ( October 2020 , SynOpen)

   null (Ed.)

   Abstract Amines such as 1,2,3,4-tetrahydroisoquinoline undergo redox­-neutral annulations with ortho-(nitromethyl)benzaldehyde. Benzoic­ acid acts as a promoter in these reactions, which involve concurrent amine α-C–H bond and N–H bond functionalization. Subsequent removal of the nitro group provides access to tetrahydroprotoberberines not accessible via typical redox-annulations. Also reported are decarboxylative annulations of ortho-(nitromethyl)benzaldehyde with proline and pipecolic acid. 

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2. Transamidation of N-acyl-glutarimides with amines

   Liu, Yongmei ; Achtenhagen, Marcel ; Liu, Ruzhang ; Szostak, Michal ( February 2018 , Organic & biomolecular chemistry)

   The development of new transamidation reactions for the synthesis of amides is an important and active area of research due to the central role of amide linkage in various fields of chemistry. Herein, we report a new method for transamidation of N-acyl-glutarimides with amines under mild, metal-free conditions that relies on amide bond twist to weaken amidic resonance. A wide range of amines and functional groups, including electrophilic substituents that would be problematic in metal-catalyzed protocols, are tolerated under the reaction conditions. Mechanistic experiments implicate the amide bond twist, thermodynamic stability of the tetrahedral intermediate and leaving group ability of glutarimide as factors controlling the reactivity of this process. The method further establishes the synthetic utility of N-acyl-glutarimides as bench-stable, twist-perpendicular, amide-based reagents in acyl-transfer reactions by a metal-free pathway. The origin of reactivity of N-acyl-glutarimides in metal-free and metal-catalyzed processes is discussed and compared. 

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3. Synthesis of Symmetric and Unsymmetric Secondary Amines from the Ligand Promoted Ruthenium Catalyzed Deaminative Coupling Reaction of Primary Amines

   Arachchige, P. T. ; Hanbin Lee, H. ; Chae S. Yi, C. S. ( January 2018 , Journal of organic chemistry)

   The catalytic system generated in-situ from the tetranuclear Ru–H complex with a catechol ligand (1/L1) was found to be effective for the direct deaminative coupling of two primary amines to form secondary amines. The catalyst 1/L1 was highly chemoselective for promoting the coupling of two different primary amines to afford unsymmetric secondary amines. The analogous coupling of aniline with primary amines formed aryl-substituted secondary amines. The treatment of aniline-d7 with 4-methoxybenzylamine led to the coupling product with significant deuterium incorporation on CH2 (18% D). The most pronounced carbon isotope effect was observed on the -carbon of the product isolated from the coupling reaction of 4-methoxybenzylamine (C(1) = 1.015(2)). Hammett plot was constructed from measuring the rates of the coupling reaction of 4-methoxyaniline with a series of para-substituted benzylamines 4-X-C6H4CH2NH2 (X = OMe, Me, H, F, CF3). ( = -0.79 ± 0.1). A plausible mechanistic scheme has been proposed for the coupling reaction on the basis of these results. The catalytic coupling method provides an operationally simple and chemoselective synthesis of secondary amine products without using any reactive reagents or forming wasteful byproducts. 

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4. New particle formation from sulfuric acid and amines: Comparison of monomethylamine, dimethylamine, and trimethylamine: Particle Formation From Different Amines

   https://doi.org/10.1002/2017JD026501  

   Olenius, Tinja ; Halonen, Roope ; Kurtén, Theo ; Henschel, Henning ; Kupiainen-Määttä, Oona ; Ortega, Ismael K. ; Jen, Coty N. ; Vehkamäki, Hanna ; Riipinen, Ilona ( July 2017 , Journal of Geophysical Research: Atmospheres)
5. Palladium-catalyzed enantioselective (2-naphthyl)methylation of azaarylmethyl amines

   https://doi.org/10.1039/D2QO00273F  

   Chen, Shuguang ; Tan, Jiahong ; Xiong, Dan ; Shang, Yongjia ; Mao, Jianyou ; Walsh, Patrick J. ( May 2022 , Organic Chemistry Frontiers)

   Enantioenriched azaarylmethyl amine derivatives are useful building blocks in synthetic and medicinal chemistry. To access these valuable motifs, an enantioselective palladium-catalyzed benzylation of azaarylmethyl amine pronucleophiles is introduced. Of note, this is a rare application of asymmetric (2-naphthyl)methylation of pro-nucleophiles with high p K a values (p K a ≈ 34 in DMSO). Control experiments support the notion that the coordination of Li + to the azaaryl nitrogen plays a critical role in the substitution process. With this procedure, enantioenriched (2-naphthyl)methylene azaarylmethyl amines with a variety of azaaryl groups (pyridyl, pyrazine, quinoxaline and isoquinoline) and cyclic and acyclic amines are readily obtained with good yields and enantioselectivities up to 99%. 

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