- Hexamethyldisilazane Lithium (LiHMDS)-Promoted Hydroboration of Alkynes and Alkenes with Pinacolborane
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Lithium-promoted hydroboration of alkynes and alkenes using commercially available hexamethyldisilazane lithium as a precatalyst and HBpin as a hydride source has been developed. This method will be appealing for organic synthesis because of its remarkable substrate tolerance and good yields. Mechanistic studies revealed that the hydroboration proceeds through the in situ-formed BH3species, which acts to drive the turnover of the hydroboration of alkynes and alkenes.
- Liu, Jichao,Wu, Caiyan,Hu, Tinghui,Yang, Wei,Xie, Yaoyao,Shi, Yinyin,Liu, Qianrui,Shao, Yinlin,Zhang, Fangjun
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p. 3442 - 3452
(2022/02/23)
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- Highly efficient hydroboration of alkynes catalyzed by porous copper-organic framework under mild conditions
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The hydroboration of alkynes is crucial due to the wide applications in organic synthesis, while such reaction is often completed with low turnover frequency (TOF) value and long reaction time. Therefore, it is very important and necessary that the hydrob
- Gao, Ning,Hu, Tianding,Kang, Xiaomin,Lan, Xingwang,Wang, Zhenguang,Wu, Zhi-Lei,Zhao, Bin
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p. 250 - 257
(2021/10/25)
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- Selective hydroboration of alkynes via multisite synergistic catalysis by PCN-222(Cu)
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Zirconium-based porphyrinic MOFs (PMOFs, MOF = metal-organic framework) have gained considerable attention in the field of electric/thermo/photo-catalysis as heterogeneous single-site catalysts; however, the study on multisite synergistic catalysis of PMO
- Ma, L. J.,Tang, Z. Y.,Yuan, J. C.,Zhang, L. J.,Zhang, X. M.
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- Creating High Regioselectivity by Electronic Metal-Support Interaction of a Single-Atomic-Site Catalyst
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Ligands are the most commonly used means to control the regioselectivity of organic reactions. It is very important to develop new regioselective control methods for organic synthesis. In this study, we designed and synthesized a single-atomic-site catalyst (SAC), namely, Cu1-TiC, with strong electronic metal-support interaction (EMSI) effects by studying various reaction mechanisms. π cloud back-donation to the alkyne on the metal catalytic intermediate was enhanced during the reaction by using transient electron-rich characteristics. In this way, the reaction achieved highly linear-E-type regioselective conversion of electronically unbiased alkynes and completely avoided the formation of branched isomers (ln:br >100:1, TON up to 612, 3 times higher than previously recorded). The structural elements of the SACs were designed following the requirements of the synthesis mechanism. Every element in the catalyst played an important role in the synthesis mechanism. This demonstrated that the EMSI, which is normally thought to be responsible for the improvement in catalytic efficiency and durability in heterogeneous catalysis, now first shows exciting potential for regulating the regioselectivity in homogeneous catalysis.
- Jing, Hongyu,Li, Jiong,Li, Wen-Hao,Li, Yadong,Wang, Dingsheng,Wang, Yu,Yang, Jiarui,Zhang, Jian,Zhao, Jie
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supporting information
p. 15453 - 15461
(2021/09/30)
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- Enantioselective Copper-Catalyzed Synthesis of Trifluoromethyl-Cyclopropylboronates
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A copper-catalyzed enantioselective cyclopropanation involving trifluorodiazoethane in the presence of alkenyl boronates has been developed. This transformation enables the preparation of 2-substituted-3-(trifluoromethyl)cyclopropylboronates with high levels of stereocontrol. The products are valuable synthetic intermediates by transformation of the boronate group. This methodology can be applied to the synthesis of novel trifluoromethylated analogues of trans-2-arylcyclopropylamines, which are prevalent motifs in biologically active compounds.
- Altarejos, Julia,Carreras, Javier,Sucunza, David,Vaquero, Juan J.
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supporting information
p. 6174 - 6178
(2021/08/18)
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- Z-Selective Alkyne Functionalization Catalyzed by a trans-Dihydride N-Heterocyclic Carbene (NHC) Iron Complex
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The Z-selective functionalization of terminal alkynes is a useful transformation in organic chemistry and mainly catalyzed by noble metals. Here, we present the Z-selective hydroboration of terminal alkynes catalyzed by a stable trans-dihydride iron compl
- De Ruiter, Graham,Fridman, Natalia,Garhwal, Subhash
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supporting information
p. 13817 - 13821
(2020/10/09)
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- Cu-Catalyzed C-H Alkenylation of Benzoic Acid and Acrylic Acid Derivatives with Vinyl Boronates
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An efficient Cu-catalyzed C-H alkenylation with acyclic and cyclic vinyl boronates was realized for the first time under mild conditions. The scope of the vinyl borons and the compatibility with functional groups including heterocycles are superior than Pd-catalyzed C-H coupling with vinyl borons, providing a reliable access to multisubstituted alkenes and dienes. Subsequent hydrogenation of the product from the internal vinyl borons will lead to installation of secondary alkyls.
- Li, Jian-Jun,Wang, Cheng-Gang,Yu, Jin-Feng,Wang, Peng,Wang, Peng,Yu, Jin-Quan
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supporting information
p. 4692 - 4696
(2020/06/25)
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- Practical Solvent-Free Microwave-Assisted Hydroboration of Alkynes
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A simple and rapid protocol for the anti-Markovnikov hydroboration of alkynes assisted by microwave irradiation has been developed. Pinacolborane smoothly reacts with terminal alkynes to obtain (E)-alkenyl boronates in good yields and short reactions times in the absence of solvent. Further transformations on the carbon-boron bond of the adducts can be sequentially achieved without the need of purifying the alkenyl boronates.
- Altarejos, Julia,Sucunza, David,Vaquero, Juan J.,Carreras, Javier
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p. 3024 - 3029
(2020/05/18)
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- AgSbF6-Catalyzed: Anti -Markovnikov hydroboration of terminal alkynes
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AgSbF6-Catalyzed anti-Markovnikov addition of pinacolborane (HBpin) to terminal alkynes to produce the E-vinylboronates is reported. This efficient methodology is scalable, compatible with sterically and electronically diverse alkynes, and works at room temperature under solvent-free condition. The utility of this method is demonstrated in the facile synthesis of the clinically important (E)-2,4,3′,5′-tetramethoxystilbene.
- Mamidala, Ramesh,Pandey, Vipin K.,Rit, Arnab
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supporting information
p. 989 - 992
(2019/01/23)
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- La[N(SiMe3)2]3-Catalyzed Hydroboration of Esters and Other Challenging Unsaturated Groups
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The commercially available homoleptic lanthanum amide La[N(SiMe3)2]3 (LaNTMS) is reported to enable the hydroboration of esters using pinacolborane (HBpin) as the reducing agent. A wide range of substrates inclu
- Kang, Zihan,Xu, Xiaojuan,Xue, Mingqiang,Yan, Dandan
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p. 1142 - 1146
(2019/10/22)
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- Zinc-Catalysed Hydroboration of Terminal and Internal Alkynes
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A regioselective hydroboration of alkynes has been developed by using commercially available zinc triflate as a catalyst, in the presence of catalytic amount of NaBHEt3. The reaction tolerates a wide range of terminal alkynes having several synthetically useful functional groups and proceeds regioselectively to furnish hydroborated products in moderate to excellent yields. This system shows moderate chemoselectivity towards terminal C≡C bond over terminal and internal C=C bond and internal C≡C bond.
- Mandal, Souvik,Mandal, Sayantan,Geetharani
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supporting information
p. 4553 - 4556
(2019/08/20)
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- Aluminium complex-catalysed hydroboration of alkenes and alkynes
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We demonstrate an efficient method for the hydroboration of terminal alkenes or alkynes with pinacolborane (HBpin) using the aluminium catalyst, [κ2-{Ph2P(=Se)NCH2(C5H4N)}Al(CH3)2/sub
- Harinath, Adimulam,Banerjee, Indrani,Bhattacharjee, Jayeeta,Panda, Tarun K.
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supporting information
p. 10531 - 10536
(2019/07/09)
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- Lithium compounds as single site catalysts for hydroboration of alkenes and alkynes
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The hydroboration of alkenes and alkynes using easily accessible lithium compounds [2,6-di-tert-butyl phenolatelithium (1a) and 1,1′ dilithioferrocene (1b)] has been achieved with good yields, high functional group tolerance and excellent chemoselectivity
- Bisai, Milan Kumar,Yadav, Sandeep,Das, Tamal,Vanka, Kumar,Sen, Sakya S.
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supporting information
p. 11711 - 11714
(2019/10/02)
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- Efficient heterogeneous hydroboration of alkynes: enhancing the catalytic activity by Cu(0) incorporated CuFe2O4 nanoparticles
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CuFe2O4 magnetic nanoparticles (NPs) are typically further calcined at high temperature to eliminate the reduced state of the Cu(0) source. Here we report the discovery of Cu(0) incorporated in CuFe2O4 that enables the catalytic activity for hydroboration of alkynes to be enhanced. This catalyst system has a low working temperature and short reacting time, and wide tolerance of substituted alkynes such as ynoate, ynamide and ynone. The Cu-CuFe2O4 catalyst was prepared by a simple hydrothermal method and well characterized by SEM, TEM, PXRD, XPS and EDS. Recycling of the catalyst was also achieved without obvious loss of activity after six runs. Furthermore, the mechanism of this reaction was also investigated.
- Zeng, Xianghua,Gong, Chunhua,Guo, Haiyang,Xu, Hao,Zhang, Junyong,Xie, Jingli
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supporting information
p. 17346 - 17350
(2018/11/01)
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- N -Heterocyclic Carbene-Catalyzed Olefination of Aldehydes with Vinyliodonium Salts to Generate α,β-Unsaturated Ketones
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An organocatalyzed metal-free, direct olefination of aldehydes with vinyliodonium salts has been achieved by an N-heterocyclic carbene-promoted C-H bond activation. The reaction proceeds under very mild conditions, delivering a range of (hetero)aryl-vinyl ketones in good yields. The retention of the double bond configuration is uniformly observed, and the application of 2-methoxyphenyl auxiliary group in iodonium salts secures a complete selectivity of the vinyl transfer.
- Rajkiewicz, Adam A.,Kalek, Marcin
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supporting information
p. 1906 - 1909
(2018/04/16)
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- Enantio- and Diastereoselective Cyclopropanation of 1-Alkenylboronates: Synthesis of 1-Boryl-2,3-Disubstituted Cyclopropanes
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A novel, highly enantio- and diastereoselective synthesis of 1-boryl-2,3-disubstituted cyclopropanes has been developed by means of the cyclopropanation of alkenylboronates with ethyl diazoacetate in the presence of catalytic amounts of a chiral copper(I) complex. The products can also be directly accessed from alkynes through an operationally simple, sequential hydroboration–cyclopropanation protocol. The resulting enantioenriched 1-boryl-2,3-disubstituted cyclopropanes are versatile synthetic intermediates that undergo further transformations at the carbon–boron bond.
- Carreras, Javier,Caballero, Ana,Pérez, Pedro J.
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supporting information
p. 2334 - 2338
(2018/01/05)
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- Lewis acid catalysis: Regioselective hydroboration of alkynes and alkenes promoted by scandium triflate
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The first commercially available scandium-catalysed selective hydroboration of alkynes and alkenes with HBpin (pin = OC-Me2CMe2O) in the presence of a catalytic amount of NaHBEt3 has been developed. This protocol can be applicable to a wide range of substrates including aromatic, aliphatic with cyclic and acyclic side chains, and heteroaryl systems with broad functional-group compatibility. Mechanistic studies revealed that the reaction occurs in a syn fashion via the σ-bond metathesis between the alkenyl scandium species and HBpin.
- Mandal, Souvik,Verma, Piyush Kumar,Geetharani
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supporting information
p. 13690 - 13693
(2019/01/03)
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- Selective and efficient synthesis of trans-arylvinylboronates and trans-hetarylvinylboronates using palladium catalyzed cross-coupling
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trans-Arylvinylboronate derivatives are important synthesis blocks in natural products, pharmaceuticals and organic materials. There are only a few reaction conditions that could selectively provide trans-arylvinylboronates by Heck coupling of pinacol vin
- Liu, Zhihao,Wei, Wei,Xiong, Lu,Feng, Qiang,Shi, Yaojie,Wang, Ningyu,Yu, Luoting
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supporting information
p. 3172 - 3176
(2017/04/14)
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- Copper-catalyzed reductive borylations on water
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In this paper, we established copper catalyzed reductive borylation of terminal alkynes and diboron on water in the presence of amine. Moderate conditions enabled selective borylations of vinyl-substituted phenylacetylenes to undergo the borylation at a C–C triple bond. The Cu catalyst can be recycled for seven times.
- Tanaka, Chihiro,Nakamura, Kimiaki,Nishikata, Takashi
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p. 3999 - 4003
(2017/06/13)
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- Transition-metal-free PhI(OAc)2-promoted highly selective hydroboration of terminal alkynes under air
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A new transition-metal-free PhI(OAc)2-promoted hydroboration reaction of terminal alkynes with bis(pinacolato)diboron has been developed at room temperature under air. A series of vinyl boronates could be conveniently and efficiently obtained i
- Chen, Suyuan,Yang, Lu,Yi, Dong,Fu, Qiang,Zhang, Zhijie,Liang, Wu,Zhang, Qiang,Ji, Jianxin,Wei, Wei
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p. 26070 - 26073
(2017/07/07)
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- Hydroboration of Alkynes Catalyzed by Pyrrolide-Based PNP Pincer-Iron Complexes
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To utilize iron complexes as catalysts, the application of a well-designed ligand is critical to control the reactivity of the iron center. Recently, our group has succeeded in the synthesis of iron complexes bearing a pyrrolide-based PNP pincer ligand an
- Nakajima, Kazunari,Kato, Takeru,Nishibayashi, Yoshiaki
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supporting information
p. 4323 - 4326
(2017/08/23)
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- Lewis acid catalysis: Catalytic hydroboration of alkynes initiated by Piers' borane
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Terminal and internal alkynes are efficiently hydroborated to (E)-alkenyl pinacol boronic esters with excellent yields and selectivities using a Lewis acid catalyst. In the case of Piers' borane (HB(C6F5)2) the borane acts as a pre-catalyst generating dissymmetrically gem-diborylated species of the form RCH2CR′(Bpin)(B(C6F5)2) which are the active catalysts.
- Fleige, Mirco,M?bus, Juri,Vom Stein, Thorsten,Glorius, Frank,Stephan, Douglas W.
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supporting information
p. 10830 - 10833
(2016/09/09)
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- Ligand-free hydroboration of alkynes catalyzed by heterogeneous copper powder with high efficiency
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Regioselective hydroboration of terminal and internal alkynes is realized by using 10 mol% copper powder (0.3-1 μm) at room temperature. 24 alkynes were efficiently converted into vinylboronates in up to 96% yield without addition of any ligand or additiv
- Zhao, Jie,Niu, Zhiqiang,Fu, Hua,Li, Yadong
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supporting information
p. 2058 - 2060
(2014/03/21)
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- Straightforward iron-catalyzed synthesis of vinylboronates by the hydroboration of alkynes
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An iron-catalyzed hydroboration of alkynes to produce vinylboronates has been examined. With a straightforward system composed of iron carbonyls and pinacolborane, good to excellent yields and chemoselectivities were achieved for a variety of alkynes. Cop
- Haberberger, Michael,Enthaler, Stephan
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supporting information
p. 50 - 54
(2013/02/23)
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- Highly selective methods for synthesis of internal (α-) vinylboronates through efficient NHC-Cu-catalyzed hydroboration of terminal alkynes. Utility in chemical synthesis and mechanistic basis for selectivity
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Cu-catalyzed methods for site-selective hydroboration of terminal alkynes, where the internal or α-vinylboronate is generated predominantly (up to >98%) are presented. Reactions are catalyzed by 1-5 mol % of N-heterocyclic carbene (NHC) complexes of copper, easily prepared from N-aryl-substituted commercially available imidazolinium salts, and proceed in the presence of commercially available bis(pinacolato)diboron [B2(pin)2] and 1.1 equiv of MeOH at -50 to -15 °C in 3-24 h. Propargyl alcohol and amine and the derived benzyl, tert-butyl, or silyl ethers as well as various amides are particularly effective substrates; also suitable are a wide range of aryl-substituted terminal alkynes, where higher α-selectivity is achieved with substrates that bear an electron-withdrawing substituent. α-Selective Cu-catalyzed hydroborations are amenable to gram-scale procedures (1 mol % catalyst loading). Mechanistic studies are presented, indicating that α selectivity arises from the structural and electronic attributes of the NHC ligands and the alkyne substrates. Consistent with suggested hypotheses, catalytic reactions with a Cu complex, derived from an N-adamantyl-substituted imidazolinium salt, afford high β selectivity with the same class of substrates and under similar conditions.
- Jang, Hwanjong,Zhugralin, Adil R.,Lee, Yunmi,Hoveyda, Amir H.
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p. 7859 - 7871
(2011/06/27)
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