2077-50-1Relevant academic research and scientific papers
Electrochemical Aziridination of Internal Alkenes with Primary Amines
Bartolomeu, Aloisio de A.,Dyga, Marco,Goo?en, Lukas J.,Laudadio, Gabriele,No?l, Timothy,O?eka, Maksim,de Bruin, Bas,de Oliveira, Kleber T.,van Leest, Nicolaas P.
, p. 255 - 266 (2021/01/19)
An electrochemical approach to prepare aziridines via an oxidative coupling between alkenes and primary alkyl amines was realized. The reaction is carried out in an electrochemical flow reactor, leading to short reaction/residence times (5 min), high yields, and broad scope. At the cathode, hydrogen is generated, which can be used in a second reactor to reduce the aziridine yielding the corresponding hydroaminated product.Aziridines are useful synthetic building blocks, widely employed for the preparation of various nitrogen-containing derivatives. As the current methods require the use of prefunctionalized amines, the development of a synthetic strategy toward aziridines that can establish the union of alkenes and amines would be of great synthetic value. Herein, we report an electrochemical approach, which realizes this concept via an oxidative coupling between alkenes and primary alkylamines. The reaction is carried out in an electrochemical flow reactor leading to short reaction/residence times (5 min), high yields, and broad scope. At the cathode, hydrogen is generated, which can be used in a second reactor to reduce the aziridine, yielding the corresponding hydroaminated product. Mechanistic investigations and DFT calculations revealed that the alkene is first anodically oxidized and subsequently reacted with the amine coupling partner.The central tenet in modern synthetic methodology is to develop new methods only using widely available organic building blocks. As a direct consequence, new activation strategies are required to cajole the coupling partners to react and, subsequently, forge new and useful chemical bonds. Using electrochemical activation, our methodology enables for the first time the direct coupling between olefins and amines to yield aziridines. Aziridines display interesting pharmacological activity and serve as valuable synthetic intermediates to prepare diverse nitrogen-containing derivatives. Interestingly, the sole byproduct generated in this process is hydrogen, which can be subsequently used to reduce the aziridine into the corresponding hydroaminated product. Hence, this electrochemical methodology can be regarded as green and sustainable from the vantage point of upgrading simple and widely available commodity chemicals.
Nickel-Catalyzed Alkylation or Reduction of Allylic Alcohols with Alkyl Grignard Reagents
Yang, Bo,Wang, Zhong-Xia
, p. 4772 - 4784 (2020/05/01)
By choosing different phosphine ligands, nickel-catalyzed selective alkylation and reduction of allylic alcohols with alkyl Grignard reagents were performed. The reaction using Ni(dppe)Cl2 as the catalyst resulted in the cross-coupling of allylic alcohols with primary alkyl Grignard reagents and cyclopropylmagnesium bromide. The reaction catalyzed by the combination of Ni(PCy3)2Cl2 and dcype led to the reduction of allylic alcohols. Secondary alkyl Grignard reagents except cyclopropylmagnesium bromide always led to reduction of allylic alcohols using either Ni(dppe)Cl2 or Ni(PCy3)2Cl2/dcype as the catalyst. In the reductive reaction β-H-containing alkyl Grignard reagents were required.
Cobalt-Catalyzed Z to e Isomerization of Alkenes: An Approach to (E)-β-Substituted Styrenes
Liu, Hongmei,Xu, Man,Cai, Cheng,Chen, Jianhui,Gu, Yugui,Xia, Yuanzhi
supporting information, p. 1193 - 1198 (2020/02/04)
An efficient cobalt-catalyzed Z to E isomerization of β-substituted styrenes using the amido-diphosphine ligand was developed, delivering the (E)-isomers with good functional tolerance and high stereoselectivity. The reaction could be scaled up to gram-scale with a catalyst loading of 0.1 mol %, using a mixture of (Z)- and (E)-alkene as the starting material. Preliminary mechanistic studies indicated that cobalt(I)-hydride and a benzylic-cobalt species were probably involved in the reaction, as supported by experiments and DFT calculations.
Radical Cation Diels-Alder Reactions by TiO2 Photocatalysis
Nakayama, Kaii,Maeta, Naoya,Horiguchi, Genki,Kamiya, Hidehiro,Okada, Yohei
supporting information, p. 2246 - 2250 (2019/04/10)
Radical cation Diels-Alder reactions by titanium dioxide (TiO2) photocatalysis in lithium perchlorate/nitromethane solution are described. TiO2 photocatalysis promotes reactions between electron-rich dienes and dienophiles, which would otherwise be difficult to accomplish due to electronic mismatching. The reactions are triggered by hole oxidation of the dienophile and are completed by the excited electron reduction of the radical cation intermediate at the dispersed surface in the absence of any sacrificial substrate.
Nickel-Catalyzed Allylic C(sp2)–H Activation: Stereoselective Allyl Isomerization and Regiospecific Allyl Arylation of Allylarenes
Wu, Qiang,Wang, Lanlan,Jin, Rizhe,Kang, Chuanqing,Bian, Zheng,Du, Zhijun,Ma, Xiaoye,Guo, Haiquan,Gao, Lianxun
, p. 5415 - 5422 (2016/11/22)
Stereoselective allyl isomerization and regiospecific allyl arylation reactions of allylarenes with a catalytic system comprising nickel(II) with an aryl Grignard reagent were studied. Both reactions are triggered by allylic internal C(sp2)–H activation by in-situ-formed Ni0, which is inserted into the C–H bond at the 2-position of the allyl moiety without a directing group. The isomerization of allylarene to 1-propenylarene favors the E isomer and proceeds with quantitative conversion. The arylation takes place through oxidative cross-coupling of allylarenes with excess Grignard reagent. It occurs regiospecifically at the position of C(sp2)–H activation and represents a new method for the synthesis of 1,1-disubstituted olefins. The results of deuterium labeling experiments reveal an alkenyl/alkyl mechanism involving allylic internal C(sp2)–H activation and multiple intermolecular 1,2-, 1,3-, and 2,3-hydride shifts. These methods represent new approaches to the functionalization of olefins, and the mechanistic investigations could be helpful for the discovery and design of new strategies for olefin functionalization.
Synthesis of Amino-ADT Provides Access to Hydrolytically Stable Amide-Coupled Hydrogen Sulfide Releasing Drug Targets
Hammers, Matthew D.,Singh, Loveprit,Montoya, Leticia A.,Moghaddam, Alan D.,Pluth, Michael D.
supporting information, p. 1349 - 1353 (2016/06/01)
As additional physiological functions of hydrogen sulfide (H2S) are discovered, developing practical methods for exogenous H2S delivery is important. In particular, nonsteroidal anti-inflammatory drugs (NSAIDs) functionalized with H2S-releasing anethole dithiolethione (ADT-OH) through ester bonds are being investigated for their combined anti-inflammatory and antioxidant potential. The chemical robustness of the connection between drug and H2S-delivery components, however, is a key and controllable linkage in these compounds. Because esters are susceptible to hydrolysis, particularly under acidic conditions such as stomach acid in oral drug delivery applications, we report here a simple synthesis of amino-ADT (ADT-NH2) and provide conditions for successful ADT-NH2 derivatization with the drugs naproxen and valproic acid. Using UV-vis spectroscopy and HPLC analysis, we demonstrate that amide-functionalized ADT derivatives are significantly more resistant to hydrolysis than ester-functionalized ADT derivatives.
A facile and convenient sequential homobimetallic catalytic approach towards β-methylstyrenes. A one-pot Stille cross-coupling/isomerization strategy
Simonetti, Sebastian O.,Larghi, Enrique L.,Kaufman, Teodoro S.
, p. 3735 - 3743 (2014/06/09)
An efficient one-pot synthetic approach towards β-methylstyrenes is reported. The transformation, based on sequential homobimetallic catalysis, involves a Stille cross-coupling reaction between aryl halides and allyltributylstannane, followed by an in situ palladium-catalyzed conjugative isomerization. The reaction was optimized, and the best results were obtained with 10 mol% Pd(PPh3)2Cl2, 8.0 equiv. LiCl, and 0.5 equiv. PPh3 in diglyme at 130 °C for 12 h. It was demonstrated that the reaction tolerates a wide variety of functional groups. This journal is the Partner Organisations 2014.
KINETICS OF ISOMERIZATION OF ALLYLBENZENE AND ITS DERIVATIVES
Polkanov, M. A.,Shapiro, I. O.,Chernoplekova, V. A.,Shatenshtein, A. I.
, p. 1123 - 1127 (2007/10/02)
The kinetics of isomerization with migration of the double bond in allylbenzene and its derivatives were measured in the lithium tert-butoxide-N,N-dimethylacetamide and potassium tert-butoxide-tert-butyl alcohol catalytic systems.The composition of the catalytically active particles in these solvents was established.The dependence of the isomerization rate of substitued allylbenzenes on the position and electronic chracteristics of the substituents is described by the Hammett equation.The effects of substituents and the characteristics of the catalytic systems on thekinetics of the ionization of substituted toluenes and the isomerization of substituted allylbenzenes are similar.It is concluded that these reactions have a common mechanism.
