- Nickel-catalyzed vinylation of aryl chlorides and bromides with vinyl ZnBr · MgBrCl
-
The Ni-catalyzed cross-coupling of aryl halides and vinylzinc bromide for the synthesis of styrene derivatives was investigated. Of the catalysts surveyed, the combination of Ni(acac)2 and Xantphos was found to be the most effective for this cr
- Yamamoto, Tetsuya,Yamakawa, Tetsu
-
-
Read Online
- Hexacationic Dendriphos ligands in the Pd-catalyzed Suzuki-Miyaura cross-coupling reaction: Scope and mechanistic studies
-
The combination of Pd2dba3·CHCl3 and hexacationic triarylphosphine-based Dendriphos ligands (1-3) leads to a highly active catalytic system in the Suzuki-Miyaura cross-coupling reaction. Under relatively mild reaction conditions, nonactivated aryl bromides and activated aryl chlorides can be coupled at a low Pd loading (0.1 mol %). The observed activity of this catalytic system, in particular in coupling reactions of aryl chlorides, is dramatically higher than that of conventional Pd catalysts employing triarylphosphine ligands. Through control and poisoning experiments, it is concluded that a homogeneous Pd(0)-Dendriphos complex is the active species in this catalytic system. Despite their triarylphosphine-based structure, Dendriphos ligands behave as very bulky phosphine ligands and lead to a preferential formation of coordinatively unsaturated and catalytically active Pd(0) species, which explains the observed high catalytic activity for these systems. The presence of six permanent cationic charges in the backbone of this class of ligands is proposed to result in a significant interligand Coulombic repulsion and plays a crucial role in their bulky behavior. In the coupling reactions of activated aryl chlorides, a positive dendritic kinetic effect was observed among the different Dendriphos generations, indicating an increased ability of the higher ligand generations to stabilize the active species due to steric effects. For aryl bromides, no dendritic effect was observed due to a shift in the rate-determining step in the catalytic cycle, from oxidative addition for aryl chlorides to transmetalation for aryl bromides.
- Snelders, Dennis J. M.,Van Koten, Gerard,Klein Gebbink, Robertus J. M.
-
-
Read Online
- Palladium-Catalyzed Tail-to-Tail Reductive Dimerization of Terminal Alkynes to 2,3-Dibranched Butadienes
-
The palladium-catalyzed tail-to-tail reductive dimerization of terminal alkynes is described for the first time. Aromatic terminal alkynes bearing diverse and sensitive functional groups as well as aliphatic terminal alkynes are efficiently transformed to 2,3-dibranched butadienes. The key to achieve a selective tail-to-tail reductive dimerization reaction is to control appropriately the acidity of the reaction solution, which is accomplished by a combined use of pivalic acid and para-toluenesulfonic acid. The tail-to-tail reductive dimerization reaction is proposed to proceed via a cationic alkenyl palladium intermediate under acidic conditions.
- Guo, Hongyu,Zhang, Sheng,Li, Yang,Yu, Xiaoqiang,Feng, Xiujuan,Yamamoto, Yoshinori,Bao, Ming
-
supporting information
(2022/02/21)
-
- Functionalized styrene synthesis via palladium-catalyzed C[sbnd]C cleavage of aryl ketones
-
We report herein the synthesis of functionalized styrenes via palladium-catalyzed Suzuki–Miyaura cross-coupling reaction between aryl ketone derivatives and potassium vinyltrifluoroborate. The employment of pyridine-oxazoline ligand was the key to the cleavage of unstrained C[sbnd]C bond. A variety of functional groups and biologically important moleculars were well tolerated. The orthogonal Suzuki–Miyaura coupling demonstrated the synthetic practicability.
- Zhang, Xu,Wang, Zhen-Yu,Wang, Xing,Xu, Hui,Dai, Hui-Xiong
-
supporting information
(2022/03/31)
-
- Charge Neutral [Cu2L2] and [Pd2L2] Metallocycles: Self-Assembly, Aggregation, and Catalysis
-
A range of morphologically distinct metallosupramolecular Cu(II) and Pd(II) complexes has been constructed, based on the tritopic ligand 1,1′,1″-(benzene-1,3,5-triyl)tris(4,4-dimethylpentane-1,3-dione) (H3L). By control of the reaction conditions, it is possible to generate distinct coordination assemblies possessing either macrocyclic or polymeric structures and more importantly distinct activity in catalysis of the Suzuki-Miyaura cross-coupling.
- Ko?odziejski, Micha?,Brock, Aidan J.,Kurpik, Gracjan,Walczak, Anna,Li, Feng,Clegg, Jack K.,Stefankiewicz, Artur R.
-
p. 9673 - 9679
(2021/06/30)
-
- Olefination via Cu-Mediated Dehydroacylation of Unstrained Ketones
-
The dehydroacylation of ketones to olefins is realized under mild conditions, which exhibits a unique reaction pathway involving aromatization-driven C-C cleavage to remove the acyl moiety, followed by Cu-mediated oxidative elimination to form an alkene between the α and β carbons. The newly adopted N′-methylpicolinohydrazonamide (MPHA) reagent is key to enable efficient cleavage of ketone C-C bonds at room temperature. Diverse alkyl- and aryl-substituted olefins, dienes, and special alkenes are generated with broad functional group tolerance. Strategic applications of this method are also demonstrated.
- Dong, Guangbin,Xu, Yan,Zhou, Xukai
-
supporting information
p. 20042 - 20048
(2021/12/03)
-
- Nickel-Catalyzed Reductive Cross-Coupling of Aryl Bromides with Vinyl Acetate in Dimethyl Isosorbide as a Sustainable Solvent
-
A nickel-catalyzed reductive cross-coupling has been achieved using (hetero)aryl bromides and vinyl acetate as the coupling partners. This mild, applicable method provides a reliable access to a variety of vinyl arenes, heteroarenes, and benzoheterocycles, which should expand the chemical space of precursors to fine chemicals and polymers. Importantly, a sustainable solvent, dimethyl isosorbide, is used, making this protocol more attractive from the point of view of green chemistry.
- Huang, Xia,Jin, Jian,Lei, Chuanhu,Su, Mincong
-
supporting information
(2022/01/15)
-
- Activation of Aryl Carboxylic Acids by Diboron Reagents towards Nickel-Catalyzed Direct Decarbonylative Borylation
-
The Ni-catalyzed decarbonylative borylation of (hetero)aryl carboxylic acids with B2cat2 has been achieved without recourse to any additives. This Ni-catalyzed method exhibits a broad substrate scope covering poorly reactive non-ortho-substituted (hetero)aryl carboxylic acids, and tolerates diverse functional groups including some of the groups active to Ni0 catalysts. The key to achieve this decarbonylative borylation reaction is the choice of B2cat2 as a coupling partner that not only acts as a borylating reagent, but also chemoselectively activates aryl carboxylic acids towards oxidative addition of their C(acyl)?O bond to Ni0 catalyst via the formation of acyloxyboron compounds. A combination of experimental and computational studies reveals a detailed plausible mechanism for this reaction system, which involves a hitherto unknown concerted decarbonylation and reductive elimination step that generates the aryl boronic ester product. This mode of boron-promoted carboxylic acid activation is also applicable to other types of reactions.
- Deng, Xi,Guo, Jiandong,Su, Weiping,Wang, Xiaotai,Zhang, Xiaofeng
-
supporting information
p. 24510 - 24518
(2021/08/12)
-
- Site-Selective Acceptorless Dehydrogenation of Aliphatics Enabled by Organophotoredox/Cobalt Dual Catalysis
-
The value of catalytic dehydrogenation of aliphatics (CDA) in organic synthesis has remained largely underexplored. Known homogeneous CDA systems often require the use of sacrificial hydrogen acceptors (or oxidants), precious metal catalysts, and harsh reaction conditions, thus limiting most existing methods to dehydrogenation of non- or low-functionalized alkanes. Here we describe a visible-light-driven, dual-catalyst system consisting of inexpensive organophotoredox and base-metal catalysts for room-temperature, acceptorless-CDA (Al-CDA). Initiated by photoexited 2-chloroanthraquinone, the process involves H atom transfer (HAT) of aliphatics to form alkyl radicals, which then react with cobaloxime to produce olefins and H2. This operationally simple method enables direct dehydrogenation of readily available chemical feedstocks to diversely functionalized olefins. For example, we demonstrate, for the first time, the oxidant-free desaturation of thioethers and amides to alkenyl sulfides and enamides, respectively. Moreover, the system's exceptional site selectivity and functional group tolerance are illustrated by late-stage dehydrogenation and synthesis of 14 biologically relevant molecules and pharmaceutical ingredients. Mechanistic studies have revealed a dual HAT process and provided insights into the origin of reactivity and site selectivity.
- Zhou, Min-Jie,Zhang, Lei,Liu, Guixia,Xu, Chen,Huang, Zheng
-
supporting information
p. 16470 - 16485
(2021/10/20)
-
- Vinyl Thianthrenium Tetrafluoroborate: A Practical and Versatile Vinylating Reagent Made from Ethylene
-
The use of vinyl electrophiles in synthesis has been hampered by the lack of access to a suitable reagent that is practical and of appropriate reactivity. In this work we introduce a vinyl thianthrenium salt as an effective vinylating reagent. The bench-stable, crystalline reagent can be readily prepared from ethylene gas at atmospheric pressure in one step and is broadly useful in the annulation chemistry of (hetero)cycles, N-vinylation of heterocyclic compounds, and palladium-catalyzed cross-coupling reactions. The structural features of the thianthrene core enable a distinct synthesis and reactivity profile, unprecedented for other vinyl sulfonium derivatives.
- Juliá, Fabio,Paulus, Fritz,Ritter, Tobias,Yan, Jiyao
-
supporting information
p. 12992 - 12998
(2021/09/03)
-
- N-Atom Deletion in Nitrogen Heterocycles
-
Excising the nitrogen in secondary amines, and coupling the two residual fragments is a skeletal editing strategy that can be used to construct molecules with new skeletons, but which has been largely unexplored. Here we report a versatile method of N-atom excision from N-heterocycles. The process uses readily available N-heterocycles as substrates, and proceeds by N-sulfonylazidonation followed by the rearrangement of sulfamoyl azide intermediates, providing various cyclic products. Examples are provided of deletion of nitrogen from natural products, synthesis of chiral O-heterocycles from commercially available chiral β-amino alcohols, formal inert C?H functionalization through a sequence of N-directed C?H functionalization and N-atom deletion reactions in which the N-atom can serve as a traceless directing group.
- Cai, Wangshui,Guo, Ting,Li, Guigen,Lu, Hongjian,Qin, Haitao,Wang, Shuang
-
p. 20678 - 20683
(2021/08/25)
-
- Method for reducing alkyne into olefin by taking water as hydrogen source under catalysis of nickel
-
The invention discloses a method for reducing alkyne into olefin by taking water as a hydrogen source under the catalysis of nickel, which comprises the following steps: placing alkyne in a solvent to react under the action of a nickel catalyst, a ligand, alkali, a boron reagent and a hydrogen source, and carrying out post-treatment to obtain olefin, and the hydrogen source is water. According to the invention, a cheap metal nickel catalyst is combined with a boron reagent to activate water, so that hydrogen transfer is realized, and the use of dangerous hydrogen is avoided. The method has good stereoselectivity, no excessive hydrogenation product alkane is generated, conditions are mild, the highest yield can reach 99%, and the method has good application prospects.
- -
-
Paragraph 0071-0074
(2021/06/26)
-
- KO-t-Bu Catalyzed Thiolation of β-(Hetero)arylethyl Ethers via MeOH Elimination/hydrothiolation
-
Herein, we describe a KO-t-Bu catalyzed thiolation of β-(hetero)arylethyl ethers through MeOH elimination to form (hetero)arylalkenes followed by anti-Markovnikov hydrothiolation to afford linear thioethers. The system works well with a variety of β-(hetero)arylethyl ethers, including electron-deficient, electron-neutral, electron-rich, and branched substrates and a range of aliphatic and aromatic thiols.
- Shigeno, Masanori,Shishido, Yoshiteru,Hayashi, Kazutoshi,Nozawa-Kumada, Kanako,Kondo, Yoshinori
-
supporting information
p. 3932 - 3935
(2021/08/24)
-
- Method for preparing olefin compound under alkaline condition
-
The invention relates to a method for preparing an olefin compound under an alkaline condition. The method comprises the following steps: adding a solvent and an alkali catalyst into long-chain alcohol serving as a raw material, introducing sulfuryl fluoride gas, stirring for reaction, and separating and purifying to obtain the olefin compound. The olefin compound has a structural formula shown in the description; and in the formula, R is phenyl, substituted phenyl, heterocyclic aryl, fused ring aryl, substituted fused ring aryl or alkyl. An alkali-promoted alcohol-to-olefin conversion method developed by the invention is mild in reaction condition, simple and convenient to operate and low in instrument and equipment requirements, the long-chain alcohol is used as a reaction raw material, the price is low, the source is wide, and the yield of the prepared olefin compound is high; and the method effectively avoids the influence of acidic conditions on part of groups (acetal, ketal, epoxy and the like), is efficient in reaction and wide in substrate application range, can tolerate most of functional groups, and provides a new path for synthesis of complex olefins.
- -
-
Paragraph 0018-0020
(2021/05/29)
-
- Illuminating Stannylation
-
We have developed photoboosted stannylation reactions of terminal alkynes (linear-selective hydrostannylation) and fluoroarenes (defluorostannylation), in which the stannyl anion is photoexcited to an excited triplet (T1) stannyl diradical species. This u
- Sakamoto, Kyoka,Nagashima, Yuki,Wang, Chao,Miyamoto, Kazunori,Tanaka, Ken,Uchiyama, Masanobu
-
supporting information
p. 5629 - 5635
(2021/05/04)
-
- Copper-Catalyzed and Proton-Directed Selective Hydroxymethylation of Alkynes with CO2
-
An intriguing strategy for copper-catalyzed hydroxymethylation of alkynes with CO2 and hydrosilane was developed. Switched on/off a proton source, for example, tBuOH, direct hydroxymethylation and reductive hydroxymethylation could be triggered selectively, delivering a series of allylic alcohols and homobenzylic alcohols, respectively, with high levels of Z/E, regio- and enantioselectivity. Such a selective synthesis is attributed to the differences in response of vinylcopper intermediate to proton and CO2. The protonation of vinylcopper species is demonstrated to be prior to hydroxymethylation, thus allowing a diversion from direct alkyne hydroxymethylation to reductive hydroxymethylation in the presence of suitable proton.
- Wang, Mei-Yan,Jin, Xin,Wang, Xiaofei,Xia, Shumei,Wang, Yue,Huang, Shouying,Li, Ying,He, Liang-Nian,Ma, Xinbin
-
supporting information
p. 3984 - 3988
(2020/12/25)
-
- Silver-Catalyzed [3+1+1] Annulation of Nitrones with Isocyanoacetates as an Approach to 1,4,5-Trisubstituted Imidazoles
-
A silver-catalyzed protocol for [3+1+1] annulation of nitrones and isocyanoacetates is reported. The reaction is proposed to proceed through sequential [3+2] cycloaddition, ring-opening, cyclization-oxidation, and dealkylation, allowing access to a broad scope of valuable polysubstituted imidazoles in high yields.
- Lv, Lanlan,Chen, Yan,Shatskiy, Andrey,Liu, Jian-Quan,Liu, Xiaoyi,K?rk?s, Markus D.,Wang, Xiang-Shan
-
supporting information
p. 964 - 968
(2020/12/25)
-
- Electrochemical fluorosulfonylation of styrenes
-
An environmentally friendly and efficient electrochemical fluorosulfonylation of styrenes has been developed. With the use of sulfonylhydrazides and triethylamine trihydrofluoride, a diverse array of β-fluorosulfones could be readily obtained. This reaction features mild conditions and a broad substrate scope, which could also be conveniently extended to a gram-scale preparation.
- Jiang, Yi-Min,Wu, Shao-Fen,Yan, Hong,Ye, Ke-Yin,Yu, Yi,Yuan, Yaofeng
-
supporting information
p. 11481 - 11484
(2021/11/16)
-
- Electrochemistry enabled selective vicinal fluorosulfenylation and fluorosulfoxidation of alkenes
-
Both sulfur and fluorine play important roles in organic synthesis, the life science, and materials science. The direct incorporation of these elements into organic scaffolds with precise control of the oxidation states of sulfur moieties is of great significance. Herein, we report the highly selective electrochemical vicinal fluorosulfenylation and fluorosulfoxidation reactions of alkenes, which were enabled by the unique ability of electrochemistry to dial in the potentials on demand. Preliminary mechanistic investigations revealed that the fluorosulfenylation reaction proceeded through a radical-polar crossover mechanism involving a key episulfonium ion intermediate. Subsequent electrochemical oxidation of fluorosulfides to fluorosulfoxides were readily achieved under a higher applied potential with the adventitious H2O in the reaction mixture.
- Jiang, Yimin,Shi, Zhaojiang,Wu, Jinnan,Wu, Shaofen,Ye, Keyin,Yu, Yi,Yuan, Yaofeng
-
supporting information
(2021/11/17)
-
- Zinc salt-catalyzed reduction of α-aryl imino esters, diketones and phenylacetylenes with water as hydrogen source
-
The zinc salt-catalyzed reduction of α-aryl imino esters, diketones and phenylacetylenes with water as hydrogen source and zinc as reductant was successfully conducted. The presented method provides a low-cost, environmentally friendly and practical preparation of α-aryl amino esters, α-hydroxyketones and phenylethylenes. By using D2O as deuterium source, the corresponding products were obtained in high efficiency with excellent deuterium incorporation rate, which gives a cheap and safe tool for access to valuable deuterium-labelled compounds. This journal is
- Shen, Guoli,Liu, Haojie,Chen, Jingchao,He, Zhenxiu,Zhou, Yongyun,Wang, Lin,Luo, Yang,Su, Zhimin,Fan, Baomin
-
supporting information
p. 3601 - 3610
(2021/05/04)
-
- Chemodivergent Synthesis of One-Carbon-Extended Alcohols via Copper-Catalyzed Hydroxymethylation of Alkynes with Formic Acid
-
The development of selective catalytic reactions that utilize easily available reagents for the efficient synthesis of alcohols is a long-standing goal of chemical research. Here an intriguing strategy for the chemodivergent copper-catalyzed hydroxymethylation of alkynes with formic acid and hydrosilane has been developed. By simply tuning the amount of formic acid and reaction temperature, distinct one-carbon-extended primary alcohols, that is, allylic alcohols and β-branched alkyl alcohols, were produced with high levels of Z/E-, regio-, and enantioselectivity.
- Jin, Xin,Fu, Hong-Chen,Wang, Mei-Yan,Huang, Shouying,Wang, Yue,He, Liang-Nian,Ma, Xinbin
-
supporting information
p. 4997 - 5001
(2021/06/28)
-
- An Electroreductive Approach to Radical Silylation via the Activation of Strong Si-Cl Bond
-
The construction of C(sp3)-Si bonds is important in synthetic, medicinal, and materials chemistry. In this context, reactions mediated by silyl radicals have become increasingly attractive but methods for accessing these intermediates remain limited. We present a new strategy for silyl radical generation via electroreduction of readily available chlorosilanes. At highly biased potentials, electrochemistry grants access to silyl radicals through energetically uphill reductive cleavage of strong Si-Cl bonds. This strategy proved to be general in various alkene silylation reactions including disilylation, hydrosilylation, and allylic silylation under simple and transition-metal-free conditions.
- Lu, Lingxiang,Siu, Juno C.,Lai, Yihuan,Lin, Song
-
supporting information
p. 21272 - 21278
(2020/12/21)
-
- Iron-Catalyzed Direct Julia-Type Olefination of Alcohols
-
Herein, we report an iron-catalyzed, convenient, and expedient strategy for the synthesis of styrene and naphthalene derivatives with the liberation of dihydrogen. The use of a catalyst derived from an earth-abundant metal provides a sustainable strategy to olefins. This method exhibits wide substrate scope (primary and secondary alcohols) functional group tolerance (amino, nitro, halo, alkoxy, thiomethoxy, and S- A nd N-heterocyclic compounds) that can be scaled up. The unprecedented synthesis of 1-methyl naphthalenes proceeds via tandem methenylation/double dehydrogenation. Mechanistic study shows that the cleavage of the C-H bond of alcohol is the rate-determining step.
- Landge, Vinod G.,Babu, Reshma,Yadav, Vinita,Subaramanian, Murugan,Gupta, Virendrakumar,Balaraman, Ekambaram
-
p. 9876 - 9886
(2020/09/03)
-
- Carbosulfenylation of Alkenes with Organozinc Reagents and Dimethyl(methylthio)sulfonium Trifluoromethanesulfonate
-
The electrophilic alkylthiolation of alkenes, initiated by dimethyl(methylthio)sulfonium salts and the subsequent addition of various heteronucleophilies has been well-established. Regarding the use of carbon nucleophiles, however, only carefully designed sp-type carbon sources have been successfully applied. We herein present our findings on the methylthiolation of alkenes with dimethyl(methylthio)sulfonium trifluoromethanesulfonate, followed by carbon-carbon bond formation in the presence of organozinc reagents, thus achieving a catalyst-free protocol toward to the carbosulfenylation of alkenes.
- Tang, Meizhong,Han, Shuxiong,Huang, Shenglan,Huang, Shenlin,Xie, Lan-Gui
-
supporting information
p. 9729 - 9734
(2020/12/21)
-
- Copper-Catalyzed Defluorinative Hydroarylation of Alkenes with Polyfluoroarenes
-
A catalytic defluorinative hydroarylation of alkenes with polyfluoroarenes in the presence of dppbz-ligated Cu catalyst and silanes was developed. This method provides a straightforward and alternative avenue to synthetic important polyfluorinated arenes with readily available and bench-stable alkenes as latent nucleophiles, and therefore avoids conventional reliance on stoichiometric quantities of organometallic reagents. This reaction proceeds under very mild conditions and exhibits good functional group compatibility and high level of regioselectivity. The synthetic potential of this method was further demonstrated by a gram-scale synthesis, and an array of experimental studies were also carried out to elaborate the probable mechanism.
- Fu, Bin,Li, Xiaohong,Xiong, Tao,Yuan, Xiuping,Zhang, Qian,Zhang, Qiao
-
supporting information
p. 23056 - 23060
(2020/10/19)
-
- Method for efficiently preparing styrene and deuterated styrene compounds
-
The invention discloses a method for efficiently preparing a styrene compound and a deuterated styrene compound. A phenylacetylene compound and water or heavy water are used as reaction raw materials;lewis acid is used as a catalyst; reacting and synthesizing in an organic solvent under a reducing agent are carried out to obtain a target product styrene compound or deuterated styrene compound; the reaction general formula is disclosed in the invention; the invention provides a method for preparing the styrene compound and the deuterated styrene compound, which is simple, mild, efficient and green to operate; water or heavy water is taken as a hydrogen source and a deuterium source respectively, and the process is green and environment-friendly; in addition, the method is simple and easy to operate, mild in reaction condition and high in synthesis efficiency, the yield of styrene reaches up to 99%, the yield of deuterated styrene reaches up to 99%, the deuterium doping rate reaches upto 98% (alpha) and 96% (beta), and wide application prospects are achieved.
- -
-
Paragraph 0096-0099
(2020/09/12)
-
- Hydrogenation reaction method
-
The invention relates to a hydrogenation reaction method, and belongs to the technical field of organic synthesis. The hydrogenation reaction method provided by the invention comprises the following steps: carrying out a hydrogen transfer reaction on a hydrogen acceptor compound, pinacol borane and a catalyst in a solvent in the presence of proton hydrogen, so that the hydrogen acceptor compound is subjected to a hydrogenation reaction; the catalyst is one or more than two of a palladium catalyst, an iridium catalyst and a rhodium catalyst; the hydrogen acceptor compound comprises one or morethan two functional groups of carbon-carbon double bonds, carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogentriple bonds and epoxy. The method is mild in reaction condition, easy to operate, high in yield, short in reaction time, wide in substrate application range, suitable for carbon-carbon double bonds,carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogen triple bonds and epoxy functional groups, good in selectivity and high in reaction specificity.
- -
-
Paragraph 0034; 0289-0292
(2020/05/14)
-
- Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration
-
A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene'diphenylmethanimine'benzaldehyde'azobenzene'nitrobenzene'quinoline'acetophenone'benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc)2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D2O and HBPin via in situ HD generation and discrimination. (Figure presented.).
- Wang, Yong,Cao, Xinyi,Zhao, Leyao,Pi, Chao,Ji, Jingfei,Cui, Xiuling,Wu, Yangjie
-
supporting information
p. 4119 - 4129
(2020/08/10)
-
- cis-Selective Transfer Semihydrogenation of Alkynes by Merging Visible-Light Catalysis with Cobalt Catalysis
-
Herein, the first example of visible-light-driven, cobalt-catalyzed transfer semihydrogenation of alkynes to alkenes is reported. It is carried out by using Ir[dF(CF3)ppy]2(dtbbpy)]PF6 as photosensitizer, CoBr2/n-Bu3P as proton-reducing catalyst, and i-Pr2NEt/AcOH as the hydrogen source. Under the established catalytic system, the semihydrogenation proceeds with Z as the major selectivity and with inhibition of over-reduction. Under mild reaction conditions, both internal and terminal alkynes, as well as reducible functional groups such as halogen, cyano, and ester, are tolerated. Preliminary mechanistic studies revealed the dual role of the photosensitizer in initiating the reaction via a single-electron transfer process and controlling the stereoselectivity via an energy transfer process. (Figure presented.).
- Ding, Hai-Xin,Guo, Wen-Jie,He, Yong-Qin,Song, Xian-Rong,Tian, Wan-Fa,Xiao, Qiang,Ye, Jing
-
supporting information
(2020/02/05)
-
- Selective Transfer Semihydrogenation of Alkynes with H2O (D2O) as the H (D) Source over a Pd-P Cathode
-
We reported a selective semihydrogenation (deuteration) of numerous terminal and internal alkynes using H2O (D2O) as the H (D) source over a Pd-P alloy cathode at a lower potential. P-doping caused the enhanced specific adsorption of alkynes and the promoted intrinsic activity for producing adsorbed atomic hydrogen (H*ads) from water electrolysis. The semihydrogenation of alkynes could be accomplished at a lower potential with up to 99 % selectivity and 78 % Faraday efficiency of alkene products, outperforming pure Pd and commercial Pd/C. This electrochemical semihydrogenation of alkynes might proceed via a H*ads addition pathway rather than a proton-coupled electron transfer process. The decreased amount of H*ads at a lower potential and the more preferential adsorption of the Pd-P to C≡C π bond than C=C moiety resulted in the excellent alkene selectivity. This method was capable of producing mono-, di-, and tri-deuterated alkenes with up to 99 % deuterium incorporation.
- Liu, Cuibo,Lu, Siyu,Wang, Changhong,Wu, Yongmeng,Zhang, Bin
-
supporting information
p. 21170 - 21175
(2020/09/11)
-
- Pd-Catalyzed Synthesis of Vinyl Arenes from Aryl Halides and Acrylic Acid
-
Acrylic acid is presented as an inexpensive, non-volatile vinylating agent in a palladium-catalyzed decarboxylative vinylation of aryl halides. The reaction proceeds through a Heck reaction of acrylic acid, immediately followed by protodecarboxylation of the cinnamic acid intermediate. The use of the carboxylate group as a deciduous directing group ensures high selectivity for monoarylated products. The vinylation process is generally applicable to diversely substituted substrates. Its utility is shown by the synthesis of drug-like molecules and the gram-scale preparation of key intermediates in drug synthesis.
- Gao, Yang,Ou, Yang,Goo?en, Lukas J.
-
supporting information
p. 8709 - 8712
(2019/06/17)
-
- Selective activation of 1,2-dichloroethane for access to β-chloroethylarenes enabled by nickel-catalyzed suzuki-type couplings
-
The selective conversion of one inactive C(sp3)-Cl bond of 1,2-dichloroethane (DCE) into C(sp3)-C(sp2) linkages for access to β-chloroethylarenes is presented here. The key to achieve the required reactivity and chemoselectivity in this synthetic method was the utilization of nickel and combinatorial nitrogen ligands as catalytic system. Synthetic advantages of this coupling chemistry included the step-simplicities to β-chloroethylarenes, the mildness and effectiveness of coupling conditions, together with the convenience for allowing further functional group transformations of the retained homobenzylic C–Cl bonds.
- Yang, Yi,Cai, Junjie,Luo, Gen,Tong, Xia,Su, Yumei,Jiang, Yan,Liu, Yingle,Zheng, Yubin,Zeng, Jijiao,Li, Chaolin
-
supporting information
p. 1130 - 1134
(2019/03/26)
-
- Nickel(ii)-catalyzed direct olefination of benzyl alcohols with sulfones with the liberation of H2
-
A nickel(ii)-catalyzed direct olefination of benzyl alcohols with sulfones to access various terminal and internal olefins with the liberation of hydrogen gas is reported.
- Landge, Vinod G.,Yadav, Vinita,Subaramanian, Murugan,Dangarh, Pragya,Balaraman, Ekambaram
-
supporting information
p. 6130 - 6133
(2019/06/03)
-
- Diboron-Assisted Copper-Catalyzed Z-Selective Semihydrogenation of Alkynes Using Ethanol as a Hydrogen Donor
-
We herein describe a B2Pin2-assisted copper-catalyzed semihydrogenation of alkynes. A variety of alkenes were obtained in good to excellent yields with Z-selectivity under mild reaction conditions. Mechanistic studies indicated that a transfer hydrogenation process was involved and ethanol acted as both a solvent and a hydrogen donor in this reaction. The present protocol enabled convenient synthesis of deuterium-substituted Z-alkenes such as Z-Combretastain A4-d2 in a high deuteration ratio by using readily available ethanol-d1 as the deuterium source.
- Bao, Hanyang,Zhou, Bingwei,Jin, Hongwei,Liu, Yunkui
-
p. 3579 - 3589
(2019/03/11)
-
- Method for selective synthesis of cis-olefins and trans-olefins by semi-reduction of alcohol hydrogen supply palladium-catalyzed alkynes
-
The invention provides a method for selective synthesis of cis-olefins and trans-olefins by semi-reduction of alcohol hydrogen supply palladium-catalyzed alkynes. The method comprises the following steps: performing alkyne reduction reaction with TEOA, NaOAc, a catalyst, alcohol and alkynes in an organic solvent and generating the cis-olefins after reaction; performing alkyne reduction reaction with a ligand, a catalyst, alcohol and alkynes in an organic solvent and generating the trans-olefins after reaction; a reactor for the reduction reaction is a sealed pressure-resistant reactor, the reduction reaction temperature is 120-150 DEG C, and the reduction reaction time is 20-48 hours; the dosage of the catalyst is 5-20 percent of the molar dosage of the alkynes, and the dosage of the alcohol is 10-100 times of the molar dosage of the alkynes; the dosage of R, R-DIPAMP is 0.5-5 times of the molar dosage of the alkynes. According to the method provided by the invention, a catalyst systemhas extremely-high chemical reaction and stereo-selectivity and can synthesize cis-olefin products or trans-olefin products with high yield; the catalyst system is good universality to a substrate, and the alkynes containing various functional groups can be efficiently subjected to the highly-selective reduction reactions.
- -
-
Paragraph 0210-0212
(2019/06/07)
-
- PdCx nanocrystals with tunable compositions for alkyne semihydrogenation
-
The palladium carbide (PdCx) material has shown great promise as an efficient catalyst for alkyne semihydrogenation. Difficulties in preparing stable PdCx catalysts have been recognized as the main obstacle. Here, we synthesized a highly stable and durable class of PdCx nanocrystals by treating pre-formed Pd nanocrystals with glucose under hydrothermal conditions. The C/Pd atomic ratios in the resultant PdCx nanocrystals can be varied from 0.04 to 0.18, simply by changing the reaction time. The catalytic results for semihydrogenation of 4-ethynyl-1,1′-biphenyl show that PdC0.18 nanocrystals exhibit an activity with a turnover frequency as high as 7896 h-1, ~7.6 and ~38 times higher than that of commercial Pd/C and Lindlar catalysts, respectively, as well as a selectivity of >99%.
- Guo, Ruiyun,Chen, Qiang,Li, Xiang,Liu, Yaming,Wang, Chaoqi,Bi, Wei,Zhao, Caiyang,Guo, Yanjun,Jin, Mingshang
-
supporting information
p. 4714 - 4720
(2019/03/07)
-
- Iron(MCP) Complexes Catalyze Aziridination with Olefins As Limiting Reagents
-
Herein described are the first efficient nitrogen-atom transfer reactions mediated by iron N,N′-dimethyl-N,N′-bis(2-pyridinylmethyl)cyclohexane-1,2-diamine- (MCP-) and 2-({1-[(pyridin-2-ylmethyl)pyrrolidin-2-yl]pyrrolidin-1-yl}methyl)pyridine-type (PDP-type) complexes. These catalysts affect styrene aziridination under mild conditions based on a limiting quantity of olefin substrate.
- Shehata, Mina F.,Ayer, Suraj K.,Roizen, Jennifer L.
-
p. 5072 - 5081
(2018/05/15)
-
- Terminal Alkenes from Acrylic Acid Derivatives via Non-Oxidative Enzymatic Decarboxylation by Ferulic Acid Decarboxylases
-
Fungal ferulic acid decarboxylases (FDCs) belong to the UbiD-family of enzymes and catalyse the reversible (de)carboxylation of cinnamic acid derivatives through the use of a prenylated flavin cofactor. The latter is synthesised by the flavin prenyltransferase UbiX. Herein, we demonstrate the applicability of FDC/UbiX expressing cells for both isolated enzyme and whole-cell biocatalysis. FDCs exhibit high activity with total turnover numbers (TTN) of up to 55000 and turnover frequency (TOF) of up to 370 min?1. Co-solvent compatibility studies revealed FDC's tolerance to some organic solvents up 20 % v/v. Using the in-vitro (de)carboxylase activity of holo-FDC as well as whole-cell biocatalysts, we performed a substrate profiling study of three FDCs, providing insights into structural determinants of activity. FDCs display broad substrate tolerance towards a wide range of acrylic acid derivatives bearing (hetero)cyclic or olefinic substituents at C3 affording conversions of up to >99 %. The synthetic utility of FDCs was demonstrated by a preparative-scale decarboxylation.
- Aleku, Godwin A.,Prause, Christoph,Bradshaw-Allen, Ruth T.,Plasch, Katharina,Glueck, Silvia M.,Bailey, Samuel S.,Payne, Karl A. P.,Parker, David A.,Faber, Kurt,Leys, David
-
p. 3736 - 3745
(2018/08/03)
-
- Chlorination of phenylallene derivatives with 1-chloro-1,2-benziodoxol-3-one: Synthesis of vicinal-dichlorides and chlorodienes
-
Allyl and vinyl chlorides represent important structural motifs in organic chemistry. Herein is described the chemoselective and regioselective reaction of aryl- and α-substituted phenylallenes with the hypervalent iodine (HVI) reagent 1-chloro-1,2-benz-iodoxol-3-one. The reaction typically results in vicinal dichlorides, except with proton-containing α-alkyl substituents, which instead give chlorinated dienes as the major product. Experimental evidence suggests that a radical mechanism is involved.
- Zhao, Zhensheng,Murphy, Graham K.
-
supporting information
p. 796 - 802
(2018/04/16)
-
- Fluorinated cyclopropanes: Synthesis and chemistry of the aryl α,β,β-trifluorocyclopropane motif
-
A general route to aryl α,β,β-trifluorocyclopropanes is reported and aryl oxidation gave the corresponding α,β,β-trifluorocyclopropane carboxylic acid. Reactions of the corresponding amides with phenol/thiophenol resulted in HF elimination and then conjugate addition. The partially fluorinated cyclopropane has a similar lipophilicity to -CF3 despite three carbon atoms, and it emerges as a novel motif for drug discovery.
- Thomson, Connor J.,Zhang, Qingzhi,Al-Maharik, Nawaf,Bühl, Michael,Cordes, David B.,Slawin, Alexandra M. Z.,O'Hagan, David
-
p. 8415 - 8418
(2018/08/04)
-
- Rapid Access to Ortho-Alkylated Vinylarenes from Aromatic Acids by Dearomatization and Tandem Decarboxylative C-H Olefination/Rearomatization
-
A two-step straightforward method for the preparation of ortho-alkylated vinylarenes from readily available benzoic acids is described. The synthetic route involves the dearomatization of benzoic acids by Birch reduction providing alkylated cyclohexa-2,5-dienyl-1-carboxylic acids. The diene subsequently undergoes a decarboxylative C-H olefination followed by rearomatization to deliver ortho-alkylated vinylarene. Mechanistic studies suggest that a Pd/Ag bimetallic catalytic system is important in the tandem decarboxylative C-H olefination/rearomatization step.
- Tsai, Hung-Chang,Huang, Yen-Hsiang,Chou, Chih-Ming
-
supporting information
p. 1328 - 1332
(2018/03/09)
-
- A highly stereoselective and efficient catalytic approach for the synthesis of trans-stilbene–arenes as π-conjugated materials
-
The potential expansion of the variety of catalytic methods for carbon–carbon bond formation is explored in many research centers all over the world. In this work, we describe very precise and controlled catalytic transformations as useful tools for the synthesis of new trans-π-conjugated molecular organic compounds. The combination of Suzuki–Miyaura coupling and cross-metathesis reactions is established as a simple and efficient method for the design of new (E)-stilbenes in the presence of well-defined transition-metal catalysts at 0.0001–1 % loadings. All of the desired products are isolated in good-to-excellent yields (up to 96 % isolated yield) with high purity.
- Majchrzak, Mariusz,Wilkowski, Grzegorz,Kubicki, Maciej
-
supporting information
p. 4291 - 4299
(2018/10/05)
-
- Synthesis of Functionalized Alkenes by a Transition-Metal-Free Zweifel Coupling
-
The Zweifel reaction is a powerful method for the synthesis of alkenes, serving as a transition-metal-free alternative to the Suzuki-Miyaura reaction. To date, the scope of the Zweifel coupling has been rather narrow and has focused mainly on the coupling of vinyllithium reagents to synthesize simple aryl- and alkyl-substituted olefins. Herein, the development of a general transition-metal-free coupling process enabling the coupling of Grignard reagents or organolithiums is described. This method enables the enantiospecific synthesis of a wide variety of functionalized acyclic and cyclic olefin products.
- Armstrong, Roly J.,Niwetmarin, Worawat,Aggarwal, Varinder K.
-
supporting information
p. 2762 - 2765
(2017/05/24)
-
- NEW PROCESSES AND INTERMEDIATES USEFUL IN SYNTHESIS OF NEP INHIBITORS
-
The invention relates to a novel process, novel process steps and novel intermediates useful in the synthesis of pharmaceutically active compounds, in particular neutral endopeptidase (NEP) inhibitors such as sacubitril, and prodrugs thereof.
- -
-
Page/Page column 50; 51
(2017/04/11)
-
- Unusual: Cis and trans architecture of dihydrofunctional double-decker shaped silsesquioxane and synthesis of its ethyl bridged π-conjugated arene derivatives
-
Double-decker silsesquioxanes have gained a high reputation in many branches of chemistry and process development. In particular, catalytic processes that convert double-decker silsesquioxanes into important functional classes of fine chemicals are a central topic of contemporary organosilicon chemistry. Although the 9,19-di(hydro)octaphenyl double-decker silsesquioxane (DDSQ-2SiH) is known, we report its cis and trans structure and X-ray structure for the first time. The combination of DDSQ-2SiH in a known hydrosilylation reaction protocol with precise reaction time control (FT-IR in situ apparatus) allowed us to selectively assemble a series of previously unreported molecular double-decker silsesquioxanes with ethyl bridged π-conjugated arenes. These compounds were used as a molecular model to obtain their respective macromolecular hybrid analogues. The obtained compounds were characterized spectroscopically and their thermal parameters were also verified.
- Walczak,Januszewski,Majchrzak,Kubicki,Dudziec,Marciniec
-
supporting information
p. 3290 - 3296
(2017/07/12)
-
- Palladium-Catalyzed Suzuki–Miyaura Cross-Coupling of Secondary α-(Trifluoromethyl)benzyl Tosylates
-
A palladium-catalyzed C(sp3)?C(sp2) Suzuki–Miyaura cross-coupling of aryl boronic acids and α-(trifluoromethyl)benzyl tosylates is reported. A readily available, air-stable palladium catalyst was employed to access a wide range of functionalized 1,1-diaryl-2,2,2-trifluoroethanes. Enantioenriched α-(trifluoromethyl)benzyl tosylates were found to undergo cross-coupling to give the corresponding enantioenriched cross-coupled products with an overall inversion in configuration. The crucial role of the CF3 group in promoting this transformation is demonstrated by comparison with non-fluorinated derivatives.
- Brambilla, Marta,Tredwell, Matthew
-
supporting information
p. 11981 - 11985
(2017/09/20)
-
- Carboxylation of styrenes with CBr4 and DMSO via cooperative photoredox and cobalt catalysis
-
Cooperative photoredox and cobalt catalyzed carboxylation of styrenes with CBr4 to afford the corresponding α,β-unsaturated carboxylic acids has been realized through radical addition and Kornblum (DMSO) oxidation. DMSO serves as the oxidant, oxygen source and solvent under these photocatalytic conditions.
- Song, Cai-Xia,Chen, Ping,Tang, Yu
-
p. 11233 - 11243
(2017/02/26)
-
- Fluorinative Rearrangements of Substituted Phenylallenes Mediated by (Difluoroiodo)toluene: Synthesis of α-(Difluoromethyl)styrenes
-
Phenylallenes undergo fluorinative rearrangement upon the action of (difluoroiodo)toluene in the presence of 20 mol % BF3?OEt2 to yield α-difluoromethyl styrenes. This unprecedented reaction was entirely chemoselective for the internal allene π bond, and showed remarkable regioselectivity during the fluorination event. Substituted phenylallenes, phenylallenes possessing both phenyl- and α-allenyl substituents, and diphenylallenes were investigated, and good functional-group compatibility was observed throughout. The ease with which allenes can be prepared on a large scale, and the operational simplicity of this reaction allowed us to rapidly access fluorine-containing building blocks that have not been accessed by conventional deoxyfluorination strategies.
- Zhao, Zhensheng,Racicot, Léanne,Murphy, Graham K.
-
supporting information
p. 11620 - 11623
(2017/09/11)
-
- Highly Selective Semihydrogenation of Alkynes to Alkenes by Using an Unsupported Nanoporous Palladium Catalyst: No Leaching of Palladium into the Reaction Mixture
-
We report the highly chemoselective and stereoselective semihydrogenation of alkynes to Z-internal and terminal alkenes by using unsupported nanoporous palladium (PdNPore) as a heterogeneous catalyst under mild reaction conditions (room temperature and 1 atm of H2). The semihydrogenation of various terminal/internal and aromatic/aliphatic alkynes afforded the corresponding alkenes in good chemical yields with high selectivities. PdNPore further showed high chemoselectivity toward terminal alkynes in the presence of internal alkynes, which has not yet been achieved using supported palladium nanoparticle catalysts. H-H heterolysis of H2 on the surface of PdNPore was strongly suggested by deuterium labeling experiments. No Pd leached from PdNPore during the reaction, and the catalyst was easily recovered and reused without a loss of activity.
- Lu, Ye,Feng, Xiujuan,Takale, Balaram S.,Yamamoto, Yoshinori,Zhang, Wei,Bao, Ming
-
p. 8296 - 8303
(2017/12/08)
-
- Nickel-catalyzed C-N bond reduction of aromatic and benzylic quaternary ammonium triflates
-
A nickel-catalyzed, efficient C-N bond reduction of aromatic and benzylic ammonium triflates has been developed using sodium isopropoxide as a reducing agent. The high efficiency, mild conditions, and good compatibility with various substituents made this method an effective supplement to the current catalytic hydrogenation reactions. Combining this reductive deamination reaction with directed aromatic functionalization reactions, a powerful strategy for regioselective functionalization of arenes was demonstrated using dialkylamine groups as traceless directing groups.
- Yi, Yuan-Qiu-Qiang,Yang, Wen-Cheng,Zhai, Dan-Dan,Zhang, Xiang-Yu,Li, Shuai-Qi,Guan, Bing-Tao
-
supporting information
p. 10894 - 10897
(2016/09/09)
-
- Direct Olefination of Alcohols with Sulfones by Using Heterogeneous Platinum Catalysts
-
Carbon-supported Pt nanoparticles (Pt/C) were found to be effective heterogeneous catalysts for the direct Julia olefination of alcohols in the presence of sulfones and KOtBu under oxidant-free conditions. Primary alcohols, including aryl, aliphatic, allyl, and heterocyclic alcohols, underwent olefination with dimethyl sulfone and aryl alkyl sulfones to give terminal and internal olefins, respectively. Secondary alcohols underwent methylenation with dimethyl sulfone. Under 2.5 bar H2, the same reaction system was effective for the transformation of alcohol OH groups to alkyl groups. Structural and mechanistic studies of the terminal olefination system suggested that Pt0 sites on the Pt metal particles are responsible for the rate-limiting dehydrogenation of alcohols and that KOtBu may deprotonate the sulfone reagent. The Pt/C catalyst was reusable after the olefination, and this method showed a higher turnover number (TON) and a wider substrate scope than previously reported methods, which demonstrates the high catalytic efficiency of the present method. Olefination of alcohols: The first heterogeneous catalytic terminal and internal olefination of primary alcohols and methylenation of secondary alcohols with sulfones, a reusable carbon-supported Pt catalyst, and KOtBu is reported (see scheme).
- Hakim Siddiki,Touchy, Abeda Sultana,Kon, Kenichi,Shimizu, Ken-Ichi
-
p. 6111 - 6119
(2016/04/26)
-
- Lewis base-assisted Lewis acid-catalyzed selective alkene formation via alcohol dehydration and synthesis of 2-cinnamyl-1,3-dicarbonyl compounds from 2-aryl-3,4-dihydropyrans
-
Acid-catalyzed dehydration of alcohols has been widely employed for the synthesis of alkenes. However, activated alcohols when employed as substrates in dehydration reactions are often plagued by the lack of alkene selectivity. In this work, the reaction system can be significantly improved through enhancing the performance of Lewis acid catalysts in the dehydration of activated alcohols by combining with a Lewis base. Observations of the reaction mechanism revealed that the Lewis base component might have changed the reaction rate order. Although both the principal and side reaction rates decreased, the effect was markedly more observed on the latter reaction. Therefore, the selectivity of the dehydration reaction was improved. On the basis of this observation, a new route to synthesize 2-cinnamyl-1,3-dicarbonyl compounds was developed by using 2-aryl-3,4-dihydropyran as a starting substrate in the presence of a Lewis acid/Lewis base combined catalyst system.
- Liu, Changhui,Pan, Bin,Gu, Yanlong
-
p. 979 - 986
(2016/07/06)
-