142-81-4Relevant articles and documents
Deoxygenative hydroboration of primary, secondary, and tertiary amides: Catalyst-free synthesis of various substituted amines
An, Duk Keun,Jaladi, Ashok Kumar,Kim, Hyun Tae,Yi, Jaeeun
, (2021/11/17)
Transformation of relatively less reactive functional groups under catalyst-free conditions is an interesting aspect and requires a typical protocol. Herein, we report the synthesis of various primary, secondary, and tertiary amines through hydroboration of amides using pinacolborane under catalyst-free and solvent-free conditions. The deoxygenative hydroboration of primary and secondary amides proceeded with excellent conversions. The comparatively less reactive tertiary amides were also converted to the corresponding N,N-diamines in moderate yields under catalyst-free conditions, although alcohols were obtained as a minor product.
Cyclic (Alkyl)(amino)carbene Ligand-Promoted Nitro Deoxygenative Hydroboration with Chromium Catalysis: Scope, Mechanism, and Applications
Zhao, Lixing,Hu, Chenyang,Cong, Xuefeng,Deng, Gongda,Liu, Liu Leo,Luo, Meiming,Zeng, Xiaoming
supporting information, p. 1618 - 1629 (2021/01/25)
Transition metal catalysis that utilizes N-heterocyclic carbenes as noninnocent ligands in promoting transformations has not been well studied. We report here a cyclic (alkyl)(amino)carbene (CAAC) ligand-promoted nitro deoxygenative hydroboration with cost-effective chromium catalysis. Using 1 mol % of CAAC-Cr precatalyst, the addition of HBpin to nitro scaffolds leads to deoxygenation, allowing for the retention of various reducible functionalities and the compatibility of sensitive groups toward hydroboration, thereby providing a mild, chemoselective, and facile strategy to form anilines, as well as heteroaryl and aliphatic amine derivatives, with broad scope and particularly high turnover numbers (up to 1.8 × 106). Mechanistic studies, based on theoretical calculations, indicate that the CAAC ligand plays an important role in promoting polarity reversal of hydride of HBpin; it serves as an H-shuttle to facilitate deoxygenative hydroboration. The preparation of several commercially available pharmaceuticals by means of this strategy highlights its potential application in medicinal chemistry.
Green method for catalyzing reduction reaction of aliphatic nitro derivative
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Paragraph 0005-0006; 0021-0024, (2021/07/31)
The invention relates to a green method for catalyzing reduction reaction of aliphatic nitro derivatives. According to the method, non-transition metal compounds, namely triethyl boron and potassium tert-butoxide, are used as a catalytic system for the first time, an aliphatic nitro derivative and pinacolborane which is low in price and easy to obtain are catalyzed to be subjected to a reduction reaction under mild conditions, and an aliphatic amine hydrochloride product is synthesized after acidification with a hydrochloric acid aqueous solution. Compared with a traditional method, the method generally has the advantages that the catalyst is cheap and easy to obtain, operation is convenient, and reaction is safe. The selective reduction reaction of the aliphatic nitro derivative catalyzed by the non-transition metal catalyst and pinacol borane is realized for the first time, and the aliphatic amine hydrochloride product is synthesized through acidification treatment of the hydrochloric acid aqueous solution, so that a practical new reaction strategy is provided for laboratory preparation or industrial production.
Hydrosilylative reduction of primary amides to primary amines catalyzed by a terminal [Ni-OH] complex
Bera, Jitendra K.,Pandey, Pragati
supporting information, p. 9204 - 9207 (2021/09/20)
A terminal [Ni-OH] complex1, supported by triflamide-functionalized NHC ligands, catalyzes the hydrosilylative reduction of a range of primary amides into primary amines in good to excellent yields under base-free conditions with key functional group tolerance. Catalyst1is also effective for the reduction of a variety of tertiary and secondary amides. In contrast to literature reports, the reactivity of1towards amide reduction follows an inverse trend,i.e., 1° amide > 3° amide > 2° amide. The reaction does not follow a usual dehydration pathway.
Method for preparing amine compound by reducing amide compound
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Paragraph 0247-0249, (2021/02/10)
The invention relates to a method for preparing an amine compound by reducing an amide compound, which comprises the following steps: in a protective atmosphere, mixing the amide compound or cyclic amide, a zirconium metal catalyst and pinacol borane, carrying out amide reduction reaction at room temperature, and carrying out aftertreatment by using an ether solution of hydrogen chloride after 12-48 hours to obtain an amine hydrochloride compound. The method is simple to operate, low in cost, good in functional group tolerance and wide in substrate range.
Deoxygenation of primary amides to amines with pinacolborane catalyzed by Ca[N(SiMe3)2]2(THF)2
Gong, Mingliang,Guo, Chenjun,Jiang, Linhong,Luo, Yunjie,Yu, Chong
supporting information, p. 1201 - 1206 (2021/05/29)
Deoxygenative reduction of amides is a challenging but favorable synthetic method of accessing amines. In the presence of a catalytic amount of Ca[N(SiMe3)2]2(THF)2, pinacolborane (HBpin) could efficiently reduce a broad scope of amides, primary amides in particular, into corresponding amines. Functional groups and heteroatoms showed good tolerance in this process of transformation, and a plausible reaction mechanism was proposed.
Reduction of Amides to Amines with Pinacolborane Catalyzed by Heterogeneous Lanthanum Catalyst La(CH2C6H4NMe2- o)3@SBA-15
Guo, Chenjun,Zhang, Fangcao,Yu, Chong,Luo, Yunjie
, p. 13122 - 13135 (2021/08/31)
Hydroboration of amides is a useful synthetic strategy to access the corresponding amines. In this contribution, it was found that the supported lanthanum benzyl material La(CH2C6H4NMe2-o)3@SBA-15 was highly active for the hydroboration of primary, secondary, and tertiary amides to amines with pinacolborane. These reactions selectively produced target amines and showed good tolerance for functional groups such as -NO2, -halogen, and -CN, as well as heteroatoms such as S and O. This reduction procedure exhibited the recyclable and reusable property of heterogeneous catalysts and was applicable to gram-scale synthesis. The reaction mechanisms were proposed based on some control experiments and the previous literature. This is the first example of hydroborative reduction of amides to amines mediated by heterogeneous catalysts.
Metal-Free Synthesis of Heteroaryl Amines or Their Hydrochlorides via an External-Base-Free and Solvent-Free C-N Coupling Protocol
Fan, Guang-Gao,Jiang, Bo-Wen,Sang, Wei,Cheng, Hua,Zhang, Rui,Yu, Bao-Yi,Yuan, Ye,Chen, Cheng,Verpoort, Francis
, p. 14627 - 14639 (2021/11/01)
Herein, a metal-free and solvent-free protocol was developed for the C-N coupling of heteroaryl halides and amines, which afforded numerous heteroaryl amines or their hydrochlorides without any external base. Further investigations elucidated that the basicity of amines and specific interactions derived from the X-ray crystallography analysis of 3j′·HCl played pivotal roles in the reactions. Moreover, this protocol was scalable to gram scales and applicable to drug molecules, which demonstrated its practical value for further applications.
Cerium-Catalyzed C-H Functionalizations of Alkanes Utilizing Alcohols as Hydrogen Atom Transfer Agents
An, Qing,Chen, Yuegang,Liu, Weimin,Pan, Hui,Wang, Xin,Wang, Ziyu,Zhang, Kaining,Zuo, Zhiwei
supporting information, p. 6216 - 6226 (2020/04/27)
Modern photoredox catalysis has traditionally relied upon metal-to-ligand charge-transfer (MLCT) excitation of metal polypyridyl complexes for the utilization of light energy for the activation of organic substrates. Here, we demonstrate the catalytic application of ligand-to-metal charge-transfer (LMCT) excitation of cerium alkoxide complexes for the facile activation of alkanes utilizing abundant and inexpensive cerium trichloride as the catalyst. As demonstrated by cerium-catalyzed C-H amination and the alkylation of hydrocarbons, this reaction manifold has enabled the facile use of abundant alcohols as practical and selective hydrogen atom transfer (HAT) agents via the direct access of energetically challenging alkoxy radicals. Furthermore, the LMCT excitation event has been investigated through a series of spectroscopic experiments, revealing a rapid bond homolysis process and an effective production of alkoxy radicals, collectively ruling out the LMCT/homolysis event as the rate-determining step of this C-H functionalization.
A cobalt phosphide catalyst for the hydrogenation of nitriles
Jitsukawa, Koichiro,Mitsudome, Takato,Mizugaki, Tomoo,Nakata, Ayako,Sheng, Min,Yamasaki, Jun
, p. 6682 - 6689 (2020/08/24)
The study of metal phosphide catalysts for organic synthesis is rare. We present, for the first time, a well-defined nano-cobalt phosphide (nano-Co2P) that can serve as a new class of catalysts for the hydrogenation of nitriles to primary amines. While earth-abundant metal catalysts for nitrile hydrogenation generally suffer from air-instability (pyrophoricity), low activity and the need for harsh reaction conditions, nano-Co2P shows both air-stability and remarkably high activity for the hydrogenation of valeronitrile with an excellent turnover number exceeding 58000, which is over 20- to 500-fold greater than that of those previously reported. Moreover, nano-Co2P efficiently promotes the hydrogenation of a wide range of nitriles, which include di- and tetra-nitriles, to the corresponding primary amines even under just 1 bar of H2 pressure, far milder than the conventional reaction conditions. Detailed spectroscopic studies reveal that the high performance of nano-Co2P is attributed to its air-stable metallic nature and the increase of the d-electron density of Co near the Fermi level by the phosphidation of Co, which thus leads to the accelerated activation of both nitrile and H2. Such a phosphidation provides a promising method for the design of an advanced catalyst with high activity and stability in highly efficient and environmentally benign hydrogenations. This journal is
