Electrochemical Synthesis of Allylic Amines from Alkenes and Amines

Allylic amines are valuable synthetic targets en route to diverse biologically active amine products. Current allylic C–H amination strate-gies remain limited with respect to the viable N-substituents. Herein we disclose a new electrochemical process to prepare aliphatic allylic amines by coupling two abundant starting materials: secondary amines and unactivated alkenes. This oxidative transformation proceeds via electrochemical generation of an electrophilic adduct between thianthrene and the alkene substrates. Treatment of these adducts with aliphatic amine nucleophiles and base provides allylic amine products in high yield. This synthetic strategy is also amenable to functionali-zation of feedstock gaseous alkenes at 1 atmosphere. In the case of 1-butene, remarkable Z-selective crotylation is observed. This strategy, however, is not limited to the synthesis of simple building blocks; complex biologically active molecules are suitable as both alkene and amine coupling partners. Preliminary mechanistic studies implicate vinylthianthrenium salts as key reactive intermediates.

Surface Functionalization of Black Phosphorus via Amine Compounds and Its Impacts on the Flame Retardancy and Thermal Decomposition Behaviors of Epoxy Resin

Recently, lots of effort has been placed into stabilizing black phosphorus (BP) in the air to improve its compatibility with polymers. Herein, BP was chemically functionalized by aliphatic amine (DETA), aromatic amine (PPDA) and cyclamine (Pid) via a nucleophilic substitution reaction, aiming to develop an intensively reactive BP flame retardant for epoxy resin (EP). The -NH2 group on BP-DETA, BP-PPDA and BP-Pid reacted with the epoxide group at different temperatures. The lowest temperature was about 150 °C for BP-DETA. The impacts of three BP-NH2 were compared on the flame retardancy and thermal decomposition of EP. At 5 wt% loading, EP/BP-NH2 all passed UL 94 V 0 rating. The limiting oxygen index (LOI) of EP/BP-PPDA was as high as 32.3%. The heat release rate (HRR) of EP/BP-DETA greatly decreased by 46% and char residue increased by 73.8%, whereas HRR of EP/BP-Pid decreased by 11.5% and char residue increased by 50.8%, compared with EP. Average effective heat of combustion (av-EHC) of EP/BP-Pid was lower than that of EP/BP-DETA and EP/BP-PPDA. In view of the flame-retardant mechanism, BP nanosheets functionalized with aliphatic amine and aromatic amine played a dominant role in the condensed phase, while BP functionalized with cyclamine was more effective in the gas phase.

Investigation of the curing process of epoxy compositions by developed amine products based on household waste polyethylene terephthalate and polycarbonate

The objects of research are oligomers-hardeners obtained by aminolysis of secondary polyethylene terephthalate (PET) and polycarbonate (PC) household waste with an aliphatic amine (PEP).The epoxy-diane resin of the ED-20 brand was chosen as the binder cured by the obtained oligomers due to its availability, good properties, acceptable viscosity, and wide applicability. The study of some parameters of the curing of thermosetting resin by industrial and synthesized hardeners is carried out.The gelation times at elevated temperatures (in the range from 50 to 100°C) and the activation energies of epoxy compositions were determined, and the conversion of epoxy groups during curing at room temperature was studied. The analysis of the obtained data showed that the structural features of macromolecules caused by the introduction of PET and PC fragments have a negligible effect on the activation energy and affect only when cured at room temperature and increase the viability of the compositions, while the gelation time at elevated temperatures in the case of all the studied hardeners is almost the same.

Enantioselective access to chiral aliphatic amines and alcohols via Ni-catalyzed hydroalkylations

Chiral aliphatic amine and alcohol derivatives are ubiquitous in pharmaceuticals, pesticides, natural products and fine chemicals, yet difficult to access due to the challenge to differentiate between the spatially and electronically similar alkyl groups. Herein, we report a nickel-catalyzed enantioselective hydroalkylation of acyl enamines and enol esters with alkyl halides to afford enantioenriched α-branched aliphatic acyl amines and esters in good yields with excellent levels of enantioselectivity. The operationally simple protocol provides a straightforward access to chiral secondary alkyl-substituted amine and secondary alkyl-substituted alcohol derivatives from simple starting materials with great functional group tolerance.

Three-component radical homo Mannich reaction

Aliphatic amine, especially tertiary aliphatic amine, is one of the most popular functionalities found in pharmaceutical agents. The Mannich reaction is a classical and widely used transformation for the synthesis of β-amino-carbonyl products. Due to an ionic nature of the mechanism, the Mannich reaction can only use non-enolizable aldehydes as substrates, which significantly limits the further applications of this powerful approach. Here we show, by employing a radical process, we are able to utilize enolizable aldehydes as substrates and develop the three-component radical homo Mannich reaction for the streamlined synthesis of γ-amino-carbonyl compounds. The electrophilic radicals are generated from thiols via the desulfurization process facilitated by visible-light, and then add to the electron-rich double bonds of the in-situ formed enamines to provide the products in a single step. The broad scope, mild conditions, high functional group tolerance, and modularity of this metal-free approach for the synthesis of complex tertiary amine scaffolds will likely be of great utility to chemists in both academia and industry.

Aliphatic Amine Mediated Assembly of [M6(mna)6] (M = Cu/Ag) into Extended Two-dimensional Structures: Synthesis, Structure and Lewis Acid Catalytic Studies

Two new two-dimensional layered compounds, [{Ag6(2-mna)6Cd(Hen)2}{Cd(en)22H2O}(H2O)8], I, and [{M6(2-mna)6Cd(Hen)2}(H2en)(H2O)10], II, (M = Cu and Ag) was prepared employing [M6-(Hmna)6]-cluster as the starting metalloligand. The metalloligand was prepared and characterized before...

β-Functionalized Push-Pull Opp-Dibenzoporphyrins as Sensitizers for Dye-Sensitized Solar Cells: The Push Group Effect

β-Functionalized push-pull zinc opp-dibenzoporphyrins were designed and synthesized as sensitizers for dye-sensitized solar cells. The utilization of arylamine to replace aliphatic amine as the donor groups has been proved to...