- Method for directly preparing alkyl borate compound from alkyl halide
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The invention relates to a method for directly preparing an alkyl borate compound from an alkyl halide, which comprises the following steps: in a protective atmosphere, mixing a titanium metal catalyst, an alkali compound, a borate compound and an alkyl halide or sulfonate compound, reacting at 35-100 DEG C for 8-24 hours, so that the alkyl halide or sulfonate compound is directly converted into the alkyl boronic acid pinacol ester compound. The method is simple to operate, low in cost, good in functional group tolerance and wide in substrate application range.
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Paragraph 0166-0168
(2021/04/14)
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- Catalytic Boration of Alkyl Halides with Borane without Hydrodehalogenation Enabled by Titanium Catalyst
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An unprecedented and general titanium-catalyzed boration of alkyl (pseudo)halides (alkyl-X, X=I, Br, Cl, OMs) with borane (HBpin, HBcat) is reported. The use of titanium catalyst can successfully suppress the undesired hydrodehalogenation products that prevail using other transition-metal catalysts. A series of synthetically useful alkyl boronate esters are readily obtained from various (primary, secondary, and tertiary) alkyl electrophiles, including unactivated alkyl chlorides, with tolerance of other reducing functional groups such as ester, alkene, and carbamate. Preliminary studies on the mechanism revealed a possible radical reaction pathway. Further extension of our strategy to aryl bromides is also demonstrated.
- Wang, Xianjin,Cui, Penglei,Xia, Chungu,Wu, Lipeng
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supporting information
p. 12298 - 12303
(2021/05/07)
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- Transition metal- And light-free radical borylation of alkyl bromides and iodides using silane
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We report operationally simple and neutral conditions for borylation of alkyl bromides and iodides to alkyl boronic esters under transition metal- and light-free conditions. A series of substrates with a wide range of functional groups were effectively transformed into the borylation products in moderate to good yields. Mechanistic studies, including radical clock experiments and DFT calculations, gave detailed insight into the radical borylation process.
- Mo, Fanyang,Sun, Beiqi,Zheng, Sihan
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supporting information
p. 5674 - 5677
(2021/06/16)
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- Hydroboration of Terminal Alkenes and trans-1,2-Diboration of Terminal Alkynes Catalyzed by a Manganese(I) Alkyl Complex
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A MnI-catalyzed hydroboration of terminal alkenes and a 1,2-diboration of terminal alkynes with pinacolborane (HBPin) is described. For alkenes, anti-Markovnikov hydroboration takes place; for alkynes the reaction proceeds with excellent trans-1,2-selectivity. The most active pre-catalyst is bench-stable alkyl bisphosphine MnI complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)]. The catalytic process is initiated by migratory insertion of a CO ligand into the Mn–alkyl bond to yield an acyl intermediate, which undergoes B?H bond cleavage of HBPin (for alkenes) and rapid C?H bond cleavage (for alkynes), forming the active MnI boryl and acetylide catalysts [Mn(dippe)(CO)2(BPin)] and [Mn(dippe)(CO)2(C≡CR)], respectively. A broad variety of aromatic and aliphatic alkenes and alkynes was efficiently and selectively borylated. Mechanistic insights are provided based on experimental data and DFT calculations revealing that an acceptorless reaction is operating involving dihydrogen release.
- Kirchner, Karl,St?ger, Berthold,Veiros, Luis F.,Weber, Stefan,Zobernig, Daniel
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supporting information
p. 24488 - 24492
(2021/10/19)
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- Synthesis and Catalytic Reactivity of Cobalt Pincer Nitrosyl Hydride Complexes
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The synthesis, characterization, and catalytic activity of low-spin {CoNO}8 pincer complexes of the type [Co(PCP)(NO)(H)] are described. These compounds are obtained either by reacting [Co(PCP)(κ2-BH4)] with NO and Et3N or, alternatively, by reacting [Co(
- Pecak, Jan,Fleissner, Sarah,Veiros, Luis F.,Pittenauer, Ernst,St?ger, Berthold,Kirchner, Karl
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p. 278 - 285
(2021/02/03)
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- Highly Selective Hydroboration of Terminal Alkenes Catalyzed by a Cobalt Pincer Complex Featuring a Central Reactive N-Heterocyclic Phosphido Fragment
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The application of a cobalt pincer complex, (PPClP)CoCl2, as a precatalyst for the hydroboration of terminal alkenes with pinacolborane (HBPin) is described. The reactions proceed rapidly under mild conditions (room temperature, 30 min) with low catalyst
- Poitras, Andrew M.,Oliemuller, Leah K.,Hatzis, Gregory P.,Thomas, Christine M.
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supporting information
p. 1025 - 1031
(2021/05/07)
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- Boron esterification reaction method without transition metal catalysis of alkyl bromide (by machine translation)
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The present invention discloses a method. of synthesizing alkylborate, using an alkyl bromide compound 1 equivalent of a diborate, 1 - 5 equivalent amount of a radical initiator in an organic solvent, 1 - 5 in the presence of a metal catalyst, 1 - 5 and r
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Paragraph 0046-0047
(2020/03/29)
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- Visible-light-mediated borylation of aryl and alkyl halides with a palladium complex
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Palladium catalyzed visible-light-mediated borylation of inactivated aryl and alkyl halides is reported; the method provided high yields and excellent functional group compatibility. Furthermore, arylsilicates were synthesized selectively using dimethylphenylsilyl boronic ester via changing the reaction conditions. Finally, the possible reaction mechanism is determined through fluorescence quenching and turn on/off experiments.
- Zhao, Jia-Hui,Zhou, Zhao-Zhao,Zhang, Yue,Su, Xuan,Chen, Xi-Meng,Liang, Yong-Min
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supporting information
p. 4390 - 4394
(2020/10/20)
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- Alkyl-halide boron esterification reaction method free from transition metal catalysis
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The invention discloses an alkyl-halide boron esterification reaction method free from transition metal catalysis. The method has the advantages that the transition metal catalysis is not needed, boric acid ester serves as a boron source, alkoxide serves
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Paragraph 0065; 0066
(2019/04/17)
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- Transition-Metal-Free Borylation of Alkyl Iodides via a Radical Mechanism
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We describe an operationally simple transition-metal-free borylation of alkyl iodides. This method uses commercially available diboron reagents as the boron source and exhibits excellent functional group compatibility. Furthermore, a diverse range of prim
- Liu, Qianyi,Hong, Junting,Sun, Beiqi,Bai, Guangcan,Li, Feng,Liu, Guoquan,Yang, Yang,Mo, Fanyang
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supporting information
(2019/07/08)
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- Silver-Catalyzed anti-Markovnikov Hydroboration of C-C Multiple Bonds
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A simple silver salt (AgOAc)-catalyzed anti-Markovnikov-selective hydroboration of alkenes, 1,3-dienes, and alkynes with pinacolborane (HBpin) has been described. This strategy provides an efficient and practical method to access various alkyl-, allyl-, a
- Wang, Yan,Guan, Rui,Sivaguru, Paramasivam,Cong, Xuefeng,Bi, Xihe
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supporting information
p. 4035 - 4038
(2019/06/14)
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- Coupling of Trifluoroacetaldehyde N-Triftosylhydrazone with Organoboronic Acids for the Synthesis of gem-Difluoroalkenes
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The synthesis of alkyl gem-difluoroalkenes remains a difficult task in organic synthesis. Here, we report a general and efficient approach for tackling this problem by gem-difluoroolefination of trifluoroacetaldehyde N-triftosylhydrazone with organoboronic acids. This protocol is operationally simple, free of transition metals, and suitable for a broad range of organoboronic acids. Moreover, the utility of the products was demonstrated by further conversion of the gem-difluorovinyl group.
- Ma, Yu,Reddy, Bhoomireddy Rajendra Prasad,Bi, Xihe
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supporting information
p. 9860 - 9863
(2019/12/24)
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- Synthesis of 2-substituted hydroquinone derivatives from 1,4-benzoquinone and allyl ethers
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B-Alkylpinacolboranes, derived from rhodium-catalyzed hydroboration of allyl ethers with pinacolborane, react with 1,4-benzoquinone under acidic, oxidizing conditions, to afford, after subsequent hydrogenation, 2-substituted hydroquinones in isolated, pur
- Kaurich, Kevin J.,Deck, Paul A.
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p. 2191 - 2196
(2018/03/28)
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- Insights into a Chemoselective Cobalt Catalyst for the Hydroboration of Alkenes and Nitriles
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A chemoselective hydroboration protocol with terminal alkene substrates is reported using an electron-rich, low-valent cobalt pincer compound. The process is catalytic and leads to exclusive formation of anti-Markovnikov products, tolerating amino groups, esters, epoxides, ketones, and other functionalities. The protocol was successfully extended toward the hydroboration of nitriles, generating the corresponding amines in moderate to good yields. Labeling studies with deuterated pinacolborane gave insights into the mechanism, establishing the intermediacy of a cobalt hydride, as well as an insertion, β-hydride elimination, and alkene isomerization pathway. These insights provide a rationale for the observed regioselectivity and allow us to propose a catalytic mechanism.
- Ibrahim, Abdulrahman D.,Entsminger, Steven W.,Fout, Alison R.
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p. 3730 - 3734
(2017/06/09)
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- Deboronative cyanation of potassium alkyltrifluoroborates: Via photoredox catalysis
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A photoredox catalytic method was developed for the direct cyanation of alkyltrifluoroborates. This reaction provides a new and useful transformation of the easily available alkyltrifluoroborates. The photocatalytic reaction can tolerate a variety of functional groups with mild reaction conditions. Mechanistic investigations are consistent with the present reaction following a radical pathway.
- Dai, Jian-Jun,Zhang, Wen-Man,Shu, Yong-Jin,Sun, Yu-Yang,Xu, Jun,Feng, Yi-Si,Xu, Hua-Jian
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supporting information
p. 6793 - 6796
(2016/06/01)
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- Boron Lewis Acid-Catalyzed Hydroboration of Alkenes with Pinacolborane: BArF3Does What B(C6F5)3Cannot Do!
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The transition-metal-free hydroboration of various alkenes with pinacolborane (HBpin) initiated by tris[3,5-bis(trifluoromethyl)phenyl]borane (BArF3) is reported. The choice of the boron Lewis acid is crucial as the more prominent boron Lewis acid tris(pentafluorophenyl)borane (B(C6F5)3) is reluctant to react. Unlike B(C6F5)3, BArF3is found to engage in substituent redistribution with HBpin, resulting in the formation of ArFBpin and the electron-deficient diboranes [H2BArF]2and [(ArF)(H)B(μ-H)2BArF2]. These in situ-generated hydroboranes undergo regioselective hydroboration of styrene derivatives as well as aliphatic alkenes with cis diastereoselectivity. Another ligand metathesis of these adducts with HBpin subsequently affords the corresponding HBpin-derived anti-Markovnikov adducts. The reactive hydroboranes are regenerated in this step, thereby closing the catalytic cycle.
- Yin, Qin,Kemper, Sebastian,Klare, Hendrik F. T.,Oestreich, Martin
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supporting information
p. 13840 - 13844
(2016/09/21)
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- Borylation of primary and secondary alkyl bromides catalyzed by Cu2O nanoparticles
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A Cu2O nanoparticle catalyzed borylation of activated and unactivated alkyl bromides is developed, using bis(pinacolato)diboron as a boron source. To the best of our knowledge this is the first report of a heterogeneous Cu2O nanocata
- Zhou, Xin-Feng,Wu, Ya-Dong,Dai, Jian-Jun,Li, Yong-Jia,Huang, Yu,Xu, Hua-Jian
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p. 46672 - 46676
(2015/06/16)
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- Rh(I)-catalyzed borylation of primary alkyl chlorides
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Rhodium-catalyzed cross-coupling reactions of unactivated primary alkyl chlorides with diboron reagents have been developed as practical methods for the synthesis of alkylboronic esters. These reactions expand the concept and utility of Rh(I)-catalyzed cr
- Gong, Tian-Jun,Jiang, Yuan-Ye,Fu, Yao
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p. 397 - 400
(2014/03/21)
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- Copper-catalyzed trifluoromethylthiolation of primary and secondary alkylboronic acids
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A Cu-catalyzed trifluoromethylthiolation of primary and secondary alkylboronic acids with an electrophilic trifluoromethylthiolating reagent is described. Tolerance for a variety of functional groups was observed.
- Shao, Xinxin,Liu, Tianfei,Lu, Long,Shen, Qilong
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supporting information
p. 4738 - 4741
(2015/04/27)
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- [(NHC)Fe(CO)4]Efficient pre-catalyst for selective hydroboration of alkenes
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[(IMes)Fe(CO)4] [IMes=1,3-bis(2,4,6-trimethylphenyl) imidazol-2-ylidene] complex was found to be an efficient pre-catalyst for the hydroboration of functional alkenes in the presence of pinacolborane at room temperature. Notably, UV irradiation
- Zheng, Jianxia,Sortais, Jean-Baptiste,Darcel, Christophe
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p. 763 - 766
(2014/03/21)
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- Alkylboronic esters from palladium- and nickel-catalyzed borylation of primary and secondary alkyl bromides
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Palladium- and nickel-catalyzed cross-coupling recations of unactivated alkyl bromides with diboron reagents have been developed as practical methods for the synthesis of primary and secondary alkylboronic esters. These reactions extend the concept and utility of Pd- and Ni-catalyzed cross-coupling of aliphatic electrophiles. They also show different substrate selectivity and ligand dependence as compared to the recently reported Cu-catalyzed borylation reaction. Copyright
- Yi, Jun,Liu, Jin-Hui,Liang, Jun,Dai, Jian-Jun,Yang, Chu-Ting,Fu, Yao,Liu, Lei
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supporting information; experimental part
p. 1685 - 1691
(2012/07/28)
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- Copper-promoted trifluoromethylation of primary and secondary alkylboronic acids
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New couple: The Cu-promoted trifluoromethylation of primary and secondary alkylboronic acids with TMSCF3 extends the scope of transition-metal-catalyzed trifluoromethylation reactions to sp 3-hybridized carbon centers. It also repres
- Xu, Jun,Xiao, Bin,Xie, Chuan-Qi,Luo, Dong-Fen,Liu, Lei,Fu, Yao
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supporting information
p. 12551 - 12554
(2013/02/22)
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- Iridium-catalyzed hydroboration of alkenes with pinacolborane
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Hydroboration of terminal and internal alkenes with pinacolborane (1.2 equiv) was carried out at room temperature in the presence of an iridium(I) catalyst (3 mol%). Addition of dppm (2 equiv) to [Ir(cod)Cl]2 gave the best catalyst for hydroboration of aliphatic terminal and internal alkenes at room temperature, resulting in addition of the boron atom to the terminal carbon of 1-alkenes with more than 99% selectivities. On the other hand, a complex prepared from dppe (2 equiv) and [Ir(cod)Cl]2 resulted in the best yields for vinylarenes such as styrene. These complexes exhibited higher levels of catalyst activity and selectivity than those of corresponding rhodium complexes. Graphical Abstract.
- Yamamoto, Yasunori,Fujikawa, Rhyou,Umemoto, Tomokazu,Miyaura, Norio
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p. 10695 - 10700
(2007/10/03)
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