1087-49-6Relevant academic research and scientific papers
Glassy carbon modified by a silver-palladium alloy: cheap and convenient cathodes for the selective reductive homocoupling of alkyl iodides
Poizot, Philippe,Jouikov, Viatcheslav,Simonet, Jacques
, p. 822 - 824 (2009)
Micrometer-thick layers of silver-palladium alloy were elaborated in order to modify the surface of glassy carbon electrodes. Such a surface modification can be readily achieved via a preliminary silver galvanostatic deposit onto carbon followed by a 'palladization' step, thanks to a simple immersion in acidic PdII-based solutions producing a displacement reaction. The as-prepared metallic interfaces exhibit outstanding catalytic capabilities especially in the cleavage of carbon-halogen bonds while being chemically/electrochemically quite stable and relatively inexpensive. More specifically, the use of such glassy carbon/Ag-Pd electrodes in dimethylformamide (DMF) containing tetraalkylammonium salts (TAA+X-) makes the one-electron reductions of primary alkyl iodides possible; this reduction leads to the formation of homodimers in high yields. Formation of a free radical as transient resulted from the homocoupling reaction.
Diversity-Oriented Synthesis of Aliphatic Fluorides via Reductive C(sp3)?C(sp3) Cross-Coupling Fluoroalkylation
Sheng, Jie,Ni, Hui-Qi,Ni, Shan-Xiu,He, Yan,Cui, Ru,Liao, Guang-Xu,Bian, Kang-Jie,Wu, Bing-Bing,Wang, Xi-Sheng
, p. 15020 - 15027 (2021)
Monofluorinated alkyl compounds are of great importance in pharmaceuticals, agrochemicals and materials. Herein, we describe a direct nickel-catalyzed monofluoromethylation of unactivated alkyl halides using a low-cost industrial raw material, bromofluoromethane, by demonstrating a general and efficient reductive cross-coupling of two alkyl halides. Results with 1-bromo-1-fluoroalkane also demonstrate the viability of monofluoroalkylation, which further established the first example of reductive C(sp3)-C(sp3) cross-coupling fluoroalkylation. These transformations demonstrate high efficiency, mild conditions, and excellent functional-group compatibility, especially for a range of pharmaceuticals and biologically active compounds. Mechanistic studies support a radical pathway. Kinetic studies reveal that the reaction is first-order dependent on catalyst and alkyl bromide whereas the generation of monofluoroalkyl radical is not involved in the rate-determining step. This strategy provides a general and efficient method for the synthesis of aliphatic fluorides.
Zn-mediated decarboxylative carbagermatranation of aliphatic: N -hydroxyphthalimide esters: Evidence for an alkylzinc intermediate
Jiang, Wei-Tao,Yang, Shuo,Xu, Meng-Yu,Xie, Xiu-Ying,Xiao, Bin
, p. 488 - 493 (2020)
Alkyl nucleophiles synthesized by decarboxylation of the corresponding N-hydroxyphthalimide esters (NHP esters) would inherit the complex structure of natural carboxylic acids and result in useful cross-coupling fragments. Herein, we report the synthesis
Analysis of key steps in the catalytic cross-coupling of alkyl electrophiles under Negishi-like conditions
Jones, Gavin D.,McFarland, Chris,Anderson, Thomas J.,Vicic, David A.
, p. 4211 - 4213 (2005)
The use of tpy′ (tpy′ = 4,4′,4″-tri-tert-butyl- terpyridine) as a ligand for nickel allows for the isolation of a Ni(I)-alkyl complex and a Ni(II)-alkyl halide complex, both of which can be used as mechanistic probes of key steps in alkyl cross-coupling reactions. The Royal Society of Chemistry 2005.
Synthesis of Asymmetrical-Terminally Bifunctionlized Alkanes by Sequential Suzuki–Miyaura Coupling Using B-Thexylboracyclanes
Suzuki, Ryota,Fuse, Shinichiro,Tanaka, Hiroshi
, p. 3478 - 3481 (2016)
A one-pot, sequential Suzuki–Miyaura coupling (SMC) using B-thexylboracyclanes is reported. We focused on a boracyclane with a bulky B-substituent as an equivalent of a terminal heterobibora-functionalized spacer. The first SMC of the boracyclane proceeded by endocyclic B–C bond cleavage due to the steric hindrance of the exocyclic B-substituent to provide borinic acids. These subsequently underwent the second SMC under harsher conditions by transfer of the less hindered primary alkyl group to provide the asymmetrically bifunctionalized alkyl chain. The seven- to five-membered boracyclanes were adaptable to the sequential SMC reactions to provide terminally bifunctional alkanes, although the efficiency of the transformation of the five-membered boracyclane was poorer than those of the others. To demonstrate the utility of the method, we successfully prepared several terminally heterobifunctional hexanes in a one-pot reaction.
Regioselective Hydroalkylation of Vinylarenes by Cooperative Cu and Ni Catalysis
Ravn, Anne K.,Johansen, Martin B.,Skrydstrup, Troels
supporting information, (2021/12/14)
Disclosed here is a dual copper and nickel catalytic system with a silyl hydride source for promoting the linear selective hydroalkylation of vinylarenes. This carbon–carbon bond-forming protocol is applied to couple a variety of functionalized vinylarenes with alkyl halides applying a nickel(II) NNN pincer complex in the presence of an NHC-ligated copper catalyst. This combination allows for a 1 mol % loading of the nickel catalyst leading to turnover numbers of up to 72. Over 40 examples are presented, including applications for pharmaceutical diversification. Labeling experiments demonstrated the regioselectivity of the reaction and revealed that the copper catalyst plays a crucial role in enhancing the rate for formation of the reactive linear alkyl nickel complex. Overall, the presented work provides a complimentary approach for hydroalkylation reactions, whilst providing a preliminary mechanistic understanding of the cooperativity between the copper and nickel complexes.
Iron-Based Catalyst for Borylation of Unactivated Alkyl Halides without Using Highly Basic Organometallic Reagents
Siddiqui, Sheema,Bhawar, Ramesh,Geetharani
, p. 1948 - 1954 (2021/01/14)
The mild borylation of alkyl bromides and chlorides with bis(neopentylglycolato)diborane (B2neop2) mediated by iron-bis amide is described. The reaction proceeds with a broad substrate scope and good functional group compatibility. Moreover, sufficient ca
Tunable and Practical Homogeneous Organic Reductants for Cross-Electrophile Coupling
Barth, Emily L.,Charboneau, David J.,Germe, Cameron C.,Hazari, Nilay,Huang, Haotian,Mercado, Brandon Q.,Uehling, Mycah R.,Zultanski, Susan L.
, p. 21024 - 21036 (2021/12/14)
The syntheses of four new tunable homogeneous organic reductants based on a tetraaminoethylene scaffold are reported. The new reductants have enhanced air stability compared to current homogeneous reductants for metal-mediated reductive transformations, such as cross-electrophile coupling (XEC), and are solids at room temperature. In particular, the weakest reductant is indefinitely stable in air and has a reduction potential of -0.85 V versus ferrocene, which is significantly milder than conventional reductants used in XEC. All of the new reductants can facilitate C(sp2)-C(sp3) Ni-catalyzed XEC reactions and are compatible with complex substrates that are relevant to medicinal chemistry. The reductants span a range of nearly 0.5 V in reduction potential, which allows for control over the rate of electron transfer events in XEC. Specifically, we report a new strategy for controlled alkyl radical generation in Ni-catalyzed C(sp2)-C(sp3) XEC. The key to our approach is to tune the rate of alkyl radical generation from Katritzky salts, which liberate alkyl radicals upon single electron reduction, by varying the redox potentials of the reductant and Katritzky salt utilized in catalysis. Using our method, we perform XEC reactions between benzylic Katritzky salts and aryl halides. The method tolerates a variety of functional groups, some of which are particularly challenging for most XEC transformations. Overall, we expect that our new reductants will both replace conventional homogeneous reductants in current reductive transformations due to their stability and relatively facile synthesis and lead to the development of novel synthetic methods due to their tunability.
Nickel-Catalyzed Cross-Electrophile C(sp3)-Si Coupling of Unactivated Alkyl Bromides with Vinyl Chlorosilanes
Duan, Jicheng,Guo, Peng,Pang, Xiaobo,Qi, Liangliang,Shu, Xing-Zhong,Wang, Yuquan
supporting information, p. 7855 - 7859 (2021/10/25)
Cross-electrophile C-Si coupling has emerged as a promising tool for the construction of organosilanes, but the potential of this method remains largely unexplored. Herein, we report a C(sp3)-Si coupling of unactivated alkyl bromides with vinyl chlorosilanes. The reaction proceeds under mild conditions, and it offers a new approach to alkylsilanes. Functionalities such as Grignard-sensitive groups (e.g., acid, amide, alcohol, ketone, and ester), acid-sensitive groups (e.g., ketal and THP protection), alkyl fluoride and chloride, aryl bromide, alkyl tosylate and mesylate, silyl ether, and amine were tolerated. Incorporation of the -Si(vinyl)R2 moiety into complex molecules and the immobilization of a glass surface by formed organosilanes were demonstrated.
Enabling the Use of Alkyl Thianthrenium Salts in Cross-Coupling Reactions by Copper Catalysis
Chen, Cheng,Lu, Hongjian,Shi, Zhuangzhi,Wang, Minyan,Zhao, Binlin
, p. 21756 - 21760 (2021/08/30)
Alkyl groups are one of the most widely used groups in organic synthesis. Here, a a series of thianthrenium salts have been synthesized that act as reliable alkylation reagents and readily engage in copper-catalyzed Sonogashira reactions to build C(sp3)?C(sp) bonds under mild photochemical conditions. Diverse alkyl thianthrenium salts, including methyl and disubstituted thianthrenium salts, are employed with great functional breadth, since sensitive Cl, Br, and I atoms, which are poorly tolerated in conventional approaches, are compatible. The generality of the developed alkyl reagents has also been demonstrated in copper-catalyzed Kumada reactions.
