6907-59-1Relevant academic research and scientific papers
Visible-light-mediated minisci C-H alkylation of heteroarenes with 4-alkyl-1,4-dihydropyridines using O2as an oxidant
Dong, Jianyang,Liu, Yuxiu,Song, Hongjian,Wang, Qingmin,Xu, Wentao,Yue, Fuyang
supporting information, p. 5599 - 5604 (2020/09/21)
Herein, we report a protocol for direct visible-light-mediated Minisci C-H alkylation reactions of N-heteroarenes with 4-alkyl-1,4-dihydropyridines at room temperature with molecular oxygen as an oxidant. The protocol permits efficient functionalization of various N-heteroarenes with a broad range of cyclic and acyclic primary, secondary, and tertiary alkyl groups and is scalable to the gram level. This mild protocol uses an inexpensive, green oxidant and is suitable for late-stage C-H alkylation of complex nitrogen-containing molecules. We demonstrated its utility by preparing or functionalizing several pharmaceuticals and natural products.
Catalytic Selective Metal-Free Cross-Coupling of Heteroaromatic N-Oxides with Organosilanes
Puthanveedu, Mahesh,Polychronidou, Vasiliki,Antonchick, Andrey P.
supporting information, p. 3407 - 3411 (2019/05/10)
A metal-free, regioselective C-H functionalization of heteroaromatic N-oxides has been developed. The method enables the synthesis of various benzylated and alkynylated N-heterocycles in a transition-metal-free manner employing organosilanes as coupling partners. The unanticipated reactivity has been exploited for the synthesis of a number of symmetrical disubstituted acetylenes from ethynyltrimethylsilane via carbon-silicon bond metathesis.
Direct Arylation of Unactivated Alkanes with Heteroarenes by Visible-Light Catalysis
Huang, Cheng,Wang, Jing-Hao,Qiao, Jia,Fan, Xiu-Wei,Chen, Bin,Tung, Chen-Ho,Wu, Li-Zhu
, p. 12904 - 12912 (2019/09/09)
The functionalization of aliphatic C-H bonds is both a major challenge and a desirable goal in organic synthesis. Here, we describe the successful arylation of unactivated alkanes with heteroarenes by using iridium polypyridyl complexes as the photocatalyst and persulfate as the HAT catalyst precursor under visible-light irradiation. This reaction features good functional group tolerance and broad scope with regard to both alkane and heteroarene substrates (37 examples), which allows direct access to alkyl-substituted N-heteroarenes, a key structural motif in natural products and bioactive molecules.
Visible-light-induced C(sp3)-H oxidative arylation with heteroarenes
Liang, Xing-An,Niu, Linbin,Wang, Shengchun,Liu, Jiamei,Lei, Aiwen
supporting information, p. 2441 - 2444 (2019/03/26)
Considering the ubiquitous C(sp3)-H and the important value of alkylated heteroarenes, developing a universal method for C(sp3)-H arylation with heteroarenes is significant. Herein, we proposed a method where Selectfluor can promote
Radical Benzylation of Quinones via C-H Abstraction
Galloway, Jordan D.,Mai, Duy N.,Baxter, Ryan D.
, p. 12131 - 12137 (2019/10/02)
Herein we report the development of radical benzylation reactions of quinones using Selectfluor and catalytic Ag(I) initiators. The reaction is believed to proceed via a C-H abstraction mechanism after Ag(I)-mediated reduction of Selectfluor. This reaction occurs under mild conditions and is effective for a variety of quinones and radical precursors bearing primary benzylic carbons. The use of preformed Ag(4-OMePy)2NO3 as a catalyst proved effective in improving the reaction efficiency by reducing unwanted degradation pathways available to Selectfluor.
Photocatalyzed ortho-Alkylation of Pyridine N-Oxides through Alkene Cleavage
Zhou, Wang,Miura, Tomoya,Murakami, Masahiro
supporting information, p. 5139 - 5142 (2018/05/30)
A photocatalyzed reaction of pyridine N-oxides with alkenes gives ortho-alkylated pyridines with cleavage of the carbon–carbon double bond. Benzyl and secondary alkyl groups are incorporated at the ortho position of pyridines in one pot.
Palladium-Catalyzed Arylation of Benzylic C-H Bonds of Azaarylmethanes with Aryl Sulfides
Gao, Ke,Yamamoto, Keita,Nogi, Keisuke,Yorimitsu, Hideki
supporting information, p. 2956 - 2960 (2017/10/06)
Benzylic C-H arylation of azaarylmethanes with aryl sulfides has been developed by using a Pd-NHC catalyst and an amide base. Various azaarylmethanes and aryl sulfides were involved in the reaction to afford the corresponding diarylmethanes in good to excellent yields. Moreover, triarylmethane synthesis was accomplished through iterative arylations of 2- or 4-methylpyridine with two different aryl sulfides.
A VERSATILE LIGAND FOR PALLADIUM-CATALYZED META-C-H FUNCTIONALIZATIONS
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Page/Page column 97; 98, (2017/11/15)
A class of mono-protected 3-amino-2- hydroxypyridine (MPAHP) ligands that enable the meta- C-H arylation of anilines, phenols, phenylacetic acids, and biologically relevant heterocyclic compounds using norbornene as a transient mediator is disclosed. The applicability of this meta-arylation methodology in the pharmaceutical industry is illustrated for heteroaryl substrates and heteroaryl iodide coupling partners, a feat made possible by using the MPAHP ligand. The enabling nature of MPAHP ligands to achieve other meta-C-H functionalization processes is also illustrated by the development of a meta-C-H amination reaction and a meta-C-H alkynylation reaction.
Oxidant-Triggered C1-Benzylation of Isoquinoline by Iodine-Catalyzed Cross-Dehydrogenative-Coupling with Methylarenes
Shi, Xin,Zhang, Feng,Luo, Wen-Kun,Yang, Luo
supporting information, p. 494 - 498 (2017/02/24)
A practical iodine-catalyzed oxidative functionalization of isoquinolines with methylarenes is developed, which can be triggered by the selected oxidants to produce C1- or N-benzyl-substituted products selectively. This method utilizes readily available isoquinolines and methylarenes as starting materials and proceeds under metal-free conditions with broad substrate scope with respect to methylarenes, avoiding the usage of expensive metal catalysts and generation of halide and metal wastes.
Ruthenium-Mediated Dual Catalytic Reactions of Isoquinoline via C?H Activation and Dearomatization for Isoquinolone
Wang, Ting-Hsuan,Lee, Wei-Chih,Ong, Tiow-Gan
, p. 2751 - 2758 (2016/09/13)
We have unraveled the ruthenium-promoted prototype reaction based on C(sp2)?C(sp3) bond formation through the reigoselective C?H activation of isoquinoline and pyridine derivatives with various alkyl halides, leading to 1-substituted isoquinoline products in good yield. This C?H catalytic reaction did not rely on chelation assistance of the directing group of the substrates. The dimer [RuCl2(p-cymene)]2in combination with an N-heterocyclic carbene ligand, adamantanecarboxylic acid and K2CO3base in N-methyl-2-pyrrolidone solution at 150 °C are the best conditions. Simultaneously, we are also able to chemically tune the reaction mode to dearomatization by adding water, leading to isoquinolone products. This reaction methodology is not suitable for other nitrogen-containing heteroarenes such as pyridazines and pyrimidines. (Figure presented.).
