157945-83-0Relevant articles and documents
Hexamethyldisilazane Lithium (LiHMDS)-Promoted Hydroboration of Alkynes and Alkenes with Pinacolborane
Liu, Jichao,Wu, Caiyan,Hu, Tinghui,Yang, Wei,Xie, Yaoyao,Shi, Yinyin,Liu, Qianrui,Shao, Yinlin,Zhang, Fangjun
, p. 3442 - 3452 (2022/02/23)
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.
Creating High Regioselectivity by Electronic Metal-Support Interaction of a Single-Atomic-Site Catalyst
Jing, Hongyu,Li, Jiong,Li, Wen-Hao,Li, Yadong,Wang, Dingsheng,Wang, Yu,Yang, Jiarui,Zhang, Jian,Zhao, Jie
supporting information, p. 15453 - 15461 (2021/09/30)
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.
Synthesis method of alkenyl borate
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Paragraph 0012; 0063-0067, (2021/10/30)
The invention discloses a synthesis method of alkenyl borate, which comprises the following steps: adding an alkyne substance, pinacolborane and a lithium amide catalyst into a reaction vessel filled with an organic solvent in a nitrogen atmosphere, stirring and mixing, uniformly mixing, reacting at the temperature of 70-110 DEG C for 18-28 hours, filtering and purifying after the reaction is finished to obtain a product, wherein the lithium amide catalyst is lithium bis(trimethylsilyl) amide; the alkyne substance is any one of substances such as phenylacetylene and 4-methyl phenylacetylene. The method is mild in reaction condition, easy to achieve and safe; the target product can be directly synthesized, an intermediate product does not need to be separated, and the highest yield can reach 98%; the catalyst is easy to prepare, and reactant raw materials are easy to obtain; the waste solution in the reaction process is less, other pollution gases and liquids are not discharged, so that the discharge of the waste solution is reduced, and the method has the advantages of protecting the environment and guaranteeing the health of operators.
Zwitterion-Initiated Hydroboration of Alkynes and Styrene
Bismuto, Alessandro,Cowley, Michael J.,Thomas, Stephen P.
supporting information, p. 2382 - 2385 (2021/01/18)
The hydroboration of alkynes and styrene with HBpin has been developed using tris(pentaflurophenyl)borane (B(C6F5)3) as the initiator of catalysis. The hydroboration is proposed to be initiated by Lewis acid activation of the alkyne by (B(C6F5)3) to form a highly reactive zwitterionic species which subsequently react with HBpin to give the alkenyl boronic ester. This zwitterion has also showed potential to be a competent catalyst for the hydroboration of styrene. The zwitterionic intermediate is analogous to that proposed in the Piers borane-catalysed hydroboration and 1,1-carboboration of alkynes with B(C6F5)3. (Figure presented.).
A relay catalysis strategy for enantioselective nickel-catalyzed migratory hydroarylation forming chiral α-aryl alkylboronates
Chen, Jian,Liang, Yong,Ma, Jiawei,Meng, Lingpu,Zhang, Yao,Zhu, Shaolin
supporting information, p. 3171 - 3188 (2021/11/16)
Ligand-controlled reactivity plays an important role in transition-metal catalysis, enabling a vast number of efficient transformations to be discovered and developed. However, a single ligand is generally used to promote all steps of the catalytic cycle (e.g., oxidative addition, reductive elimination), a requirement that makes ligand design challenging and limits its generality, especially in relay asymmetric transformations. We hypothesized that multiple ligands with a metal center might be used to sequentially promote multiple catalytic steps, thereby combining complementary catalytic reactivities through a simple combination of simple ligands. With this relay catalysis strategy (L/L?), we report here the first highly regio- and enantioselective remote hydroarylation process. By synergistic combination of a known chain-walking ligand and a simple asymmetric cross-coupling ligand with the nickel catalyst, enantioenriched α-aryl alkylboronates could be rapidly obtained as versatile synthetic intermediates through this formal asymmetric remote C(sp3)-H arylation process.
Z-Selective Synthesis of Vinyl Boronates through Fe-Catalyzed Alkyl Radical Addition
Barzanò, Guido,Cheseaux, Alexis,Hu, Xile
supporting information, (2019/01/21)
Z-Selective synthesis of vinyl boronates is challenging. This work describes Fe-catalyzed addition of alkyl radicals, formed by the corresponding alkyl halides, to ethynyl ethynylboronic acid pinacol ester that gives rise to Z-vinyl boronates in high ster
Z-Selective Synthesis of Vinyl Boronates through Fe-Catalyzed Alkyl Radical Addition
Barzanò, Guido,Cheseaux, Alexis,Hu, Xile
supporting information, p. 490 - 493 (2019/01/24)
Z-Selective synthesis of vinyl boronates is challenging. This work describes Fe-catalyzed addition of alkyl radicals, formed by the corresponding alkyl halides, to ethynyl ethynylboronic acid pinacol ester that gives rise to Z-vinyl boronates in high ster
Magnesium-Catalyzed Hydroboration of Terminal and Internal Alkynes
Magre, Marc,Maity, Bholanath,Falconnet, Alban,Cavallo, Luigi,Rueping, Magnus
supporting information, p. 7025 - 7029 (2019/04/26)
A magnesium-catalyzed hydroboration of alkynes providing good yields and selectivities for a wide range of terminal and symmetrical and unsymmetrical internal alkynes has been developed. The compatibility with many functional groups makes this magnesium c
Kinetics and Mechanism of the Arase-Hoshi R2BH-Catalyzed Alkyne Hydroboration: Alkenylboronate Generation via B-H/C-B Metathesis
Nieto-Sepulveda, Eduardo,Bage, Andrew D.,Evans, Louise A.,Hunt, Thomas A.,Leach, Andrew G.,Thomas, Stephen P.,Lloyd-Jones, Guy C.
supporting information, p. 18600 - 18611 (2019/11/19)
The mechanism of R2BH-catalyzed hydroboration of alkynes by 1,3,2-dioxaborolanes has been investigated by in situ 19F NMR spectroscopy, kinetic simulation, isotope entrainment, single-turnover labeling (10B/2H), and density functional theory (DFT) calculations. For the Cy2BH-catalyzed hydroboration 4-fluorophenylacetylene by pinacolborane, the resting state is the anti-Markovnikov addition product ArCH = CHBCy2. Irreversible and turnover-rate limiting reaction with pinacolborane (k ≈ 7 × 10-3 M-1 s-1) regenerates Cy2BH and releases E-Ar-CH═CHBpin. Two irreversible events proceed in concert with turnover. The first is a Markovnikov hydroboration leading to regioisomeric Ar-C(Bpin)═CH2. This is unreactive to pinacolborane at ambient temperature, resulting in catalyst inhibition every ～102 turnovers. The second is hydroboration of the alkenylboronate to give ArCH2CH(BCy2)Bpin, again leading to catalyst inhibition. 9-BBN behaves analogously to Cy2BH, but with higher anti-Markovnikov selectivity, a lower barrier to secondary hydroboration, and overall lower efficiency. The key process for turnover is B-H/C-B metathesis, proceeding by stereospecific transfer of the E-alkenyl group within a transient, μ-B-H-B bridged, 2-electron-3-center bonded B-C-B intermediate.
Efficient heterogeneous hydroboration of alkynes: enhancing the catalytic activity by Cu(0) incorporated CuFe2O4 nanoparticles
Zeng, Xianghua,Gong, Chunhua,Guo, Haiyang,Xu, Hao,Zhang, Junyong,Xie, Jingli
supporting information, p. 17346 - 17350 (2018/11/01)
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.
