- Reductive amination of ketones/aldehydes with amines using BH3N(C2H5)3as a reductant
-
Herein, we report the first example of efficient reductive amination of ketones/aldehydes with amines using BH3N(C2H5)3 as a catalyst and a reductant under mild conditions, affording various tertiary and secondary amines in excellent yields. A mechanistic study indicates that BH3N(C2H5)3 plays a dual function role of promoting imine and iminium formation and serving as a reductant in reductive amination. This journal is
- Zou, Qizhuang,Liu, Fei,Zhao, Tianxiang,Hu, Xingbang
-
supporting information
p. 8588 - 8591
(2021/09/04)
-
- Single Atomically Anchored Cobalt on Carbon Quantum Dots as Efficient Photocatalysts for Visible Light-Promoted Oxidation Reactions
-
Generation of efficient light-induced charge separation inside the photocatalyst is an essential factor for a high catalytic efficiency. The usual immobilization of metal or metal oxide particles on semiconductor photocatalysts offers an uncontrolled assembly of active sites during the reaction. The introduction of single metal atoms on photocatalysts can lead to extremely high atomic utilization and precise active sites. However, this approach is limited because of the lack of suitable photosensitizers for single atom immobilization. Here, we have designed photocatalytic carbon quantum dots with anchoring sites for single cobalt atoms in a defined Co-N4 structure via facile pyrolysis of vitamin B12. Carbon dots functioned as both light-harvesting antenna and support for the cobalt atom with high atom loadings up to 3.27 wt %. This new photocatalytic material demonstrated enhanced visible light absorption, efficient charge separation, and reduced electrochemical impedance, while single Co atoms acted as the active site with strong oxidative ability. As a result, the photocatalysts showed excellent visible light-promoted photocatalytic efficiency with oxygen evolution rates up to 168 μmol h-1 g-1 via water oxidation, imine formation with high conversion (~90%) and selectivity (>99%), and complete photodegradation of organic dyes.
- Wang, Qin,Li, Jin,Tu, Xianjun,Liu, Hongbo,Shu, Miao,Si, Rui,Ferguson, Calum T. J.,Zhang, Kai. A. I.,Li, Run
-
p. 734 - 743
(2020/02/04)
-
- Synthetic and theoretical investigation on the one-pot halogenation of β-amino alcohols and nucleophilic ring opening of aziridinium ions
-
Aziridinium ions are useful reactive intermediates for the synthesis of enantiomerically enriched building blocks. However, N,N-dialkyl aziridinium ions are relatively underutilized in the synthesis of optically active molecules as compared to other three
- Chen, Yunwei,Sun, Xiang,Wu, Ningjie,Li, Jingbai,Jin, Shengnan,Zhong, Yongliang,Liu, Zirui,Rogachev, Andrey,Chong, Hyun-Soon
-
p. 920 - 939
(2016/01/15)
-
- The synthesis of sterically hindered amines by a direct reductive amination of ketones
-
An atom-economical methodology for the synthesis of sterically hindered tertiary amines was developed, which is based on complementary Rh- and Ru-catalyzed direct reductive amination of ketones with primary and secondary amines using carbon monoxide as a deoxygenating agent.
- Yagafarov, Niyaz Z.,Kolesnikov, Pavel N.,Usanov, Dmitry L.,Novikov, Valentin V.,Nelyubina, Yulia V.,Chusov, Denis
-
supporting information
p. 1397 - 1400
(2016/01/25)
-
- N-alkylation of amines by homogeneous ruthenium complexes in the presence of free diphosphines
-
Chemoselective N-alkylation of amines by ruthenium complexes in the presence of free diphosphine ligands under mild conditions is described. Octyl amine and aniline were chosen as aliphatic and aromatic amines to investigate the effect of different phosphines, reaction times, and temperature on conversion, as well as selectivity towards related secondary and tertiary amines. After optimization of the reaction conditions, this catalytic system was used for N-alkylation of other amines and has shown moderate to very good yields. The reaction products were monitored by GC-MS. The crystal structure of [Ru(NO3)2CO(PPh3)2] with a monodentate and a bidentate nitrate was determined by X-ray crystallographic analysis.
- Tamaddoni Jahromi, Bahareh,Kharat, Ali Nemati
-
p. 3498 - 3508
(2014/01/06)
-
- Nonlinear taft polar free energy relationship: Reactions of N-substituted benzyl amines with benzyl bromide in methanol
-
The rates of reactions of N-substituted benzyl amines with benzyl bromide were measured using a conductivity technique in methanol medium. The reaction followed a total second-order path. The end product of the reaction is identified as dibenzyl alkyl amine (C6H5CH 2N(R)CH2C6H5). The rates increased with a decrease in the electron-donating capacity or with an increase in the Taft σ* value of electron-donating alkyl substituents (R) such as t-butyl (σ* = -0.3), i-propyl (σ* = -0.19), n-butyl (σ* = -0.13), and ethyl (σ* = -0.1) on nitrogen of the amine until the Taft σ* value becomes zero for the methyl group (σ CH 3* = 0.00), and then the rates decreased with an increase in the electron-withdrawing capacity or with an increase in the Taft σ* value of electron-withdrawing substituents (R) such H and C6H 5 (σH* = 0.49 and σC6H5= 0.6). The locus of the Taft polar free energy relationship has a maximum near the point for N-methyl benzyl amine, showing that there is a sharp change in the rate-determining step. A mechanism involving formation of an SN2-type transition state between the amine nucleophiles and the benzyl bromide and its subsequent decomposition is proposed. Activation parameters were calculated and are discussed.
- Ravi,Sanjeev,Jagannadham
-
p. 803 - 810
(2013/11/19)
-
- One-pot reductive n-alkylation with carbonyl compounds to give tertiary amines via borane reduction of imines
-
One-pot synthesis of tertiary amines via borane-mediated reduction of imines and reductive N-alkylation with carbonyl compounds is described. This protocols reducing agent is only borane in the reduction of imines, and additional reductant is not necessary in reductive N-alkylation step. When using more than two equivalents of aldehydes, reductive N-alkylation proceeded in good yield.
- Tokizane, Masashi,Sato, Kaori,Sakami, Yuki,Imori, Yoichiro,Matsuo, Chika,Ohta, Tetsuo,Ito, Yoshihiko
-
experimental part
p. 36 - 42
(2010/05/02)
-
- Oligomeric benzylsulfonium salts: Facile benzylation via high-load ROMP reagents
-
(Chemical Equation Presented) The development of high-load, oligomeric benzylsulfonium salts, generated via ring-opening metathesis polymerization, and their utility in facile benzylations of various nucleophiles is reported. These oligomeric sulfonium salts exist as free-flowing powders and are stable at room temperature. After the benzylation event, purification is attained via simple dry load/filtration, followed by solvent removal to deliver products in excellent yield and purity.
- Zhang, Mianji,Flynn, Daniel L.,Hanson, Paul R.
-
p. 3194 - 3198
(2008/02/04)
-
- Copper-catalyzed electrophilic amination of organozinc nucleophiles: Documentation of O-benzoyl hydroxylamines as broadly useful R2N(+) and RHN(+) synthons
-
This paper details new copper-catalyzed electrophilic amination reactions of diorganozinc reagents using O-benzoyl hydroxylamines as electrophilic nitrogen sources that may be accessed in one step. Simple and functionalized aryl, heteroaryl-, benzyl, n-alkyl, sec-alkyl, and tert-alkyl nucleophiles couple with R2NOC(O)Ph and RHNOC(O)Ph reagents in the presence of catalytic quantities of copper salts to provide tertiary and secondary amines, respectively, in generally good yields. In many cases, the product may be isolated analytically pure after a simple extractive workup. The amination process is shown to tolerate a significant degree of steric demand. The amination of nominally unreactive Caryl-H bonds via a sequential directed ortho metalation/transmetalation/catalytic amination reaction sequence is detailed. The direct Cu-catalyzed amination of Grignard reagents using cocatalysis by ZnCl2 is described.
- Herman, Ashley M.,Johnson, Jeffrey S.
-
p. 219 - 224
(2007/10/03)
-
- Copper-Catalyzed Electrophilic Amination of Diorganozinc Reagents
-
The copper-catalyzed electrophilic amination of diorganozinc reagents employing O-acyl N,N-dialkyl hydroxylamine derivatives as aminating agents is described. This reaction offers a general method for the preparation of tertiary amines in high yields and is noteworthy for its convenience both in terms of reaction conditions employed (room temperature, ≤1 h) and ease of product isolation (acid/base extractive workup). Copyright
- Berman, Ashley M.,Johnson, Jeffrey S.
-
p. 5680 - 5681
(2007/10/03)
-
- Intramolecular motions in a series of crystalline benzylammonium bromides and dibenzylamines studied by CP/MAS NMR
-
A series of 15 compounds including ammonium bromides containing one or two benzyl groups with H, methyl, isopropyl, tert-butyl and tert-amyl substituents and dibenzylamihe with N-isopropyl-, N-tert-butyl- and N-tert-amyl substituents have been synthesised and studied by CP/MAS NMR. The results of dynamic NMR studies on the solids suggest that there is a dramatically wide range of molecular motions occurring in this simple series of compounds: A combination of 2D CPEXSY, dynamic line shape analyses and T1ρ measurements reveals the considerable extent of intramolecular group motions including rotations of methyl, tert-butyl, tert-amyl and phenyl groups. Rates of rotation and activation parameters for these molecular motions are derived where appropriate. In the case of benzyl-tert-butylammonium bromide, where two independent molecules of the compound exist in the asymmetric unit it is shown that the independent processes of tert-butyl rotation in the two molecules have vastly different activation energies that differ by ca. 16 kJ mol-1. The extent of the motions observed suggests that commonly held prejudices about the rigidity of molecules in crystalline solids need revising.
- Riddell, Frank G.,Rogerson, Martin
-
p. 493 - 504
(2007/10/03)
-
- Stereodynamics of 2-(diethylamino)propane and 2-(dibenzylamino)propane. 1H and 13C{1H} DNMR studies. Molecular mechanics calculations
-
2-(Diethylamino)propane (DEAP) and 2-(dibenzylamino)propane (DBAP) possess similar molecular symmetries. Interconversion among the stable equilibrium conformations occurs by inversion-rotation at the pyramidal nitrogen and by isolated rotation about carbon-nitrogen bonds. In DEAP and DBAP, the fact that stable equilibrium conformations cannot have destabilizing syn-1,5 interactions between methyl or phenyl groups limits the number of equilibrium conformations that will be present at concentrations high enough to be NMR detectable. The 1H and 13C{1H} NMR spectra of DEAP at 100 K show two diastereomeric pairs of enantiomeric conformations. One pair of enantiomers has the isopropyl methine proton and both ethyl methyl groups gauche to the lone pair (75%). The other pair has the methine proton anti to the lone pair with the ethyl methyl groups respectively gauche and anti to the lone pair (25%). The barrier to inversion-rotation in DEAP (ΔG? = 6.4 kcal/mol) is higher than barriers to isolated rotation about carbon-nitrogen bonds (ΔG? = 5.3-5.7 kcal/mol). The 1H and 13C{1H} NMR spectra of DBAP at 100 K show just one pair of enantiomeric conformations that have the isopropyl methine proton and both phenyl groups gauche to the lone pair. There is no evidence in the NMR spectrum at 100 K for those conformations of DBAP that have a phenyl group anti to the lone pair. The barrier to inversion-rotation in DBAP (ΔG? = 6.4 kcal/mol) is higher than the barrier to racemization via isolated rotation about carbon-nitrogen bonds (ΔG? = 5.5 kcal/mol). Molecular mechanics calculations of conformational energies are in good agreement with the observed conformational preferences.
- Brown, Jay H.,Bushweller, C. Hackett
-
p. 12567 - 12577
(2007/10/03)
-