159087-40-8Relevant academic research and scientific papers
Ag(I)-catalyzed C-H borylation of terminal alkynes
Hu, Jiu-Rong,Liu, Lin-Hai,Hu, Xin,Ye, Hong-De
, p. 5815 - 5819 (2014)
An efficient Ag(I)-catalyzed borylation method of terminal alkynes is reported. The obtained borylated alkynes are shown to engage in C-Br, C-CN, C-N, and C-C bond formation with various reaction partners. Meanwhile the Ag(I) catalyst could be regenerated in the presence of PPh3 and BF3.
ZnBr2-Catalyzed Dehydrogenative Borylation of Terminal Alkynes
Luo, Man,Qin, Yi,Chen, Xi,Xiao, Qian,Zhao, Binlin,Yao, Weiwei,Ma, Mengtao
, p. 16666 - 16674 (2021/11/18)
The simple, commercially available ZnBr2 has been successfully employed as a highly efficient and chemoselective catalyst for the dehydrogenative borylation of terminal alkynes with HBpin under mild conditions. It shows a good tolerance toward various functional groups such as aryl, alkyl, heteroaryl, etc. The plausible reaction mechanism has been investigated based on the corresponding stoichiometric experiments and DFT calculations.
Method for removing hydroboration of aluminum chloride catalytic terminal group alkyne
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Paragraph 0043-0045, (2021/10/16)
The invention discloses a hydroboration method of an aluminum chloride catalytic terminal group alkyne, and belongs to the technical field of boronation of terminal alkynes. To the method, the terminal group alkyne is added into the aluminum chloride with
Ru-Catalyzed Geminal Hydroboration of Silyl Alkynes via a New gem-Addition Mechanism
Feng, Qiang,Wu, Haonan,Li, Xin,Song, Lijuan,Chung, Lung Wa,Wu, Yun-Dong,Sun, Jianwei
supporting information, p. 13867 - 13877 (2020/09/21)
While 1,2-addition represents the most common mode of alkyne hydroboration, herein we describe a new 1,1-hydroboration mode. It is the first demonstration of gem-(H,B) addition to an alkyne triple bond. With the superior [CpRu(MeCN)3]PF6 catalyst, a range of silyl alkynes reacted efficiently with HBpin under mild conditions to form various synthetically useful silyl vinyl boronates with complete stereoselectivity and broad functional group compatibility. An extension to germanyl alkynes and the hydrosilylation of alkynyl boronates toward the same type of products were also achieved. Mechanistically, this process features a new pathway featuring gem-(H,B) addition to form the key α-boryl-α-silyl Ru-carbene intermediate followed by silyl migration. It is believed that the orbital interaction between boron and Cβ in the coplanar relationship between the boron atom and the ruthenacyclopropene ring preceding boron migration is responsible for the new reactivity. Control experiments and DFT (including molecular dynamics) calculations provided important insights into the mechanism, which excluded the involvement of a metal vinylidene intermediate. This study represents a new step forward not only for alkyne hydroboration but also for other geminal additions of alkynes.
Oxidation of Alkynyl Boronates to Carboxylic Acids, Esters, and Amides
Li, Chenchen,Li, Ruoling,Zhang, Bing,Zhao, Pei,Zhao, Wanxiang
supporting information, p. 10913 - 10917 (2020/05/25)
A general efficient protocol was developed for the synthesis of carboxylic acids, esters, and amides through oxidation of alkynyl boronates, generated directly from terminal alkynes. This protocol represents the first example of C(sp)?B bond oxidation. This approach displays a broad substrate scope, including aryl and alkyl alkynes, and exhibits excellent functional group tolerance. Water, primary and secondary alcohols, and amines are suitable nucleophiles for this transformation. Notably, amino acids and peptides can be used as nucleophiles, providing an efficient method for the synthesis and modification of peptides. The practicability of this methodology was further highlighted by the preparation of pharmaceutical molecules.
Boron Recycling in the Metal-Free Transfer C-H Borylation of Terminal Alkynes and Heteroarenes
Desrosiers, Vincent,Fontaine, Frédéric-Georges,Garcia, Cecilia Zavaleta
, p. 11046 - 11056 (2020/11/23)
Transfer C-H borylation is an isodesmic approach to the borylation reaction using B-C-containing molecules as boron sources. In this work, we report that 2-mercaptothiazole and other analogues are active for the metal-free borylation of heterocycles and t
Copper-catalyzed dehydrogenative borylation of terminal alkynes with pinacolborane
Romero, Erik A.,Jazzar, Rodolphe,Bertrand, Guy
, p. 165 - 168 (2016/12/30)
LCuOTf complexes [L = cyclic (alkyl)(amino)carbenes (CAACs) or N-heterocyclic carbenes (NHCs)] selectively promote the dehydrogenative borylation of C(sp)-H bonds at room temperature. It is shown that σ,π-bis(copper) acetylide and copper hydride complexes are the key catalytic species.
Ligand survey results in identification of PNP pincer complexes of iridium as long-lived and chemoselective catalysts for dehydrogenative borylation of terminal alkynes
Lee, Chun-I,Demott, Jessica C.,Pell, Christopher J.,Christopher, Alyson,Zhou, Jia,Bhuvanesh, Nattamai,Ozerov, Oleg V.
, p. 6572 - 6582 (2015/10/28)
Following the report on the successful use of SiNN pincer complexes of iridium as catalysts for dehydrogenative borylation of terminal alkynes (DHBTA) to alkynylboronates, this work examined a wide variety of related pincer ligands in the supporting role in DHBTA. The ligand selection included both new and previously reported ligands and was developed to explore systematic changes to the SiNN framework (the 8-(2-diisopropylsilylphenyl)aminoquinoline). Surprisingly, only the diarylamido/bis(phosphine) PNP system showed any DHBTA reactivity. The specific PNP ligand (bearing two diisopropylphosphino side donors) used in the screen showed DHBTA activity inferior to SiNN. However, taking advantage of the ligand optimization opportunities presented by the PNP system via the changes in the substitution at phosphorus led to the discovery of a catalyst whose activity, longevity, and scope far exceeded that of the original SiNN archetype. Several Ir complexes were prepared in a model PNP system and evaluated as potential intermediates in the catalytic cycle. Among them, the (PNP)Ir diboryl complex and the borylvinylidene complex were shown to be less competent in catalysis and thus likely not part of the catalytic cycle.
Synthesis of Triborylalkenes from Terminal Alkynes by Iridium-Catalyzed Tandem C-H Borylation and Diboration
Lee, Chun-I,Shih, Wei-Chun,Zhou, Jia,Reibenspies, Joseph H.,Ozerov, Oleg V.
supporting information, p. 14003 - 14007 (2016/01/25)
A two-step reaction to convert terminal alkynes into triborylalkenes is reported. In the first step, the terminal alkyne and pinacolborane (HBpin) are converted into an alkynylboronate, which is catalyzed by an iridium complex supported by a SiNN pincer l
Catalytic dehydrogenative borylation of terminal alkynes by a SiNN pincer complex of iridium
Lee, Chun-I,Zhou, Jia,Ozerov, Oleg V.
supporting information, p. 3560 - 3566 (2013/04/23)
Compounds with carbon-boron bonds are versatile intermediates for building more complex molecules via the elaboration of the carbon-boron bonds into other carbon-element bonds. The synthesis of carbon-boron bonds by catalytic dehydrogenative borylation of carbon-hydrogen bonds with dialkoxyboranes (RO)2BH is particularly attractive. It has been demonstrated for a variety of carbon-hydrogen bond types but not for the C(sp)-H bonds of terminal alkynes, for which hydroboration of the triple bond is a competing process. We report a new iridium catalyst that is strictly chemoselective for C-H borylation of terminal alkynes. The key to the success of this catalyst appears to be the new ancillary SiNN pincer ligand that combines amido, quinoline, and silyl donors and gives rise to structurally unusual Ir complexes. A variety of terminal alkynes (RC≡C-H) can be converted to their alkynylboronates (RC≡C-Bpin, where pin = pinacolate) in high yield and purity within minutes at ambient temperature.
