174715-24-3Relevant academic research and scientific papers
C(sp3)-H Monoarylation of Methanol Enabled by a Bidentate Auxiliary
Gou, Quan,Ran, Man,Ren, Jian,Tan, Xiaoping,Yuan, Binfang,Yuan, Tengrui,Zhang, Ming-Zhong,Zhang, Xing
supporting information, p. 118 - 123 (2021/01/13)
With the assistance of a practical directing group (COAQ), the first catalytic protocol for the palladium-catalyzed C(sp3)-H monoarylation of methanol has been developed, offering an invaluable synthesis means to establish extensive derivatives of crucial arylmethanol functional fragments. Furthermore, the gram-scale reaction, broad substrate scope, excellent functional group compatibility, and even the practical synthesis of medicines further demonstrate the usefulness of this strategy.
Palladium-Catalyzed Chlorocarbonylation of Aryl (Pseudo)Halides Through In Situ Generation of Carbon Monoxide
Bismuto, Alessandro,Boehm, Philip,Morandi, Bill,Roediger, Sven
supporting information, p. 17887 - 17896 (2020/08/19)
An efficient palladium-catalyzed chlorocarbonylation of aryl (pseudo)halides that gives access to a wide range of carboxylic acid derivatives has been developed. The use of butyryl chloride as a combined CO and Cl source eludes the need for toxic, gaseous carbon monoxide, thus facilitating the synthesis of high-value products from readily available aryl (pseudo)halides. The combination of palladium(0), Xantphos, and an amine base is essential to promote this broadly applicable catalytic reaction. Overall, this reaction provides access to a great variety of carbonyl-containing products through in situ transformation of the generated aroyl chloride. Combined experimental and computational studies support a reaction mechanism involving in situ generation of CO.
B(C6F5)3-Catalyzed Highly Chemoselective Reduction of Isatins: Synthesis of Indolin-3-ones and Indolines
Jeong, Hyojin,Han, Nara,Hwang, Dong Wook,Ko, Haye Min
supporting information, p. 8150 - 8155 (2020/11/02)
A chemo- and site-selective reduction reaction of isatin derivatives using catalyst B(C6F5)3 and hydrosilanes is described. This transformation is operationally simple, proceeds under mild conditions, and is resistant to various functional groups. Thus, this efficient reaction using a combination of B(C6F5)3 and BnMe2SiH or B(C6F5)3 and Et2SiH2 could potentially be utilized to produce various indolin-3-ones and indolines, without the need for multistep procedures and metal catalysis conditions.
Carbon Dioxide-Mediated C(sp2)-H Arylation of Primary and Secondary Benzylamines
Kapoor, Mohit,Chand-Thakuri, Pratibha,Young, Michael C.
supporting information, p. 7980 - 7989 (2019/05/22)
C-C bond formation by transition metal-catalyzed C-H activation has become an important strategy to fabricate new bonds in a rapid fashion. Despite the pharmacological importance of ortho-arylbenzylamines, however, effective ortho-C-C bond formation of free primary and secondary benzylamines using PdII remains an outstanding challenge. Presented herein is a new strategy for constructing ortho-arylated primary and secondary benzylamines mediated by carbon dioxide (CO2). The use of CO2 with Pd is critical to allowing this transformation to proceed under relatively mild conditions, and mechanistic studies indicate that it (CO2) is directly involved in the rate-determining step. Furthermore, the milder temperatures furnish free amine products that can be directly used or elaborated without the need for deprotection. In cases where diarylation is possible, an interesting chelate effect is shown to facilitate selective monoarylation.
Carbon Dioxide as a Directing Group for C-H Functionalization Reactions Involving Lewis Basic Amines, Alcohols, Thiols, and Phosphines for the Synthesis of Compounds
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Paragraph 0131, (2019/07/03)
Methods of synthesizing compounds using CO2 as a directing group for C—H functionalization, and compounds made thereby, are described.
Carbon Dioxide-Mediated C(sp3)-H Arylation of Amine Substrates
Kapoor, Mohit,Liu, Daniel,Young, Michael C.
supporting information, p. 6818 - 6822 (2018/05/31)
Elaborating amines via C-H functionalization has been an important area of research over the past decade but has generally relied on an added directing group or sterically hindered amine approach. Since free-amine-directed C(sp3)-H activation is still primarily limited to cyclization reactions and to improve the sustainability and reaction scope of amine-based C-H activation, we present a strategy using CO2 in the form of dry ice that facilitates intermolecular C-H arylation. This methodology has been used to enable an operationally simple procedure whereby 1° and 2° aliphatic amines can be arylated selectively at their γ-C-H positions. In addition to potentially serving as a directing group, CO2 has also been demonstrated to curtail the oxidation of sensitive amine substrates.
A general electrochemical strategy for the Sandmeyer reaction
Liu, Qianyi,Sun, Beiqi,Liu, Zheng,Kao, Yi,Dong, Bo-Wei,Jiang, Shang-Da,Li, Feng,Liu, Guoquan,Yang, Yang,Mo, Fanyang
, p. 8731 - 8737 (2018/12/10)
Herein we report a general electrochemical strategy for the Sandmeyer reaction. Using electricity as the driving force, this protocol employs a simple and inexpensive halogen source, such as NBS, CBrCl3, CH2I2, CCl4, LiCl and NaBr for the halogenation of aryl diazonium salts. In addition, we found that these electrochemical reactions could be performed using anilines as the starting material in a one-pot fashion. Furthermore, the practicality of this process was demonstrated in the multigram scale synthesis of aryl halides using highly inexpensive graphite as the electrode. A series of detailed mechanism studies have been performed, including radical clock and radical scavenger study, cyclic voltammetry analysis and in situ electron paramagnetic resonance (EPR) analysis.
Ligand-enabled β-C-H arylation of α-amino acids using a simple and practical auxiliary
Chen, Gang,Shigenari, Toshihiko,Jain, Pankaj,Zhang, Zhipeng,Jin, Zhong,He, Jian,Li, Suhua,Mapelli, Claudio,Miller, Michael M.,Poss, Michael A.,Scola, Paul M.,Yeung, Kap-Sun,Yu, Jin-Quan
supporting information, p. 3338 - 3351 (2015/03/30)
Pd-catalyzed β-C-H functionalizations of carboxylic acid derivatives using an auxiliary as a directing group have been extensively explored in the past decade. In comparison to the most widely used auxiliaries in asymmetric synthesis, the simplicity and practicality of the auxiliaries developed for C-H activation remains to be improved. We previously developed a simple N-methoxyamide auxiliary to direct β-C-H activation, albeit this system was not compatible with carboxylic acids containing α-hydrogen atoms. Herein we report the development of a pyridine-type ligand that overcomes this limitation of the N-methoxyamide auxiliary, leading to a significant improvement of β-arylation of carboxylic acid derivatives, especially α-amino acids. The arylation using this practical auxiliary is applied to the gram-scale syntheses of unnatural amino acids, bioactive molecules, and chiral bis(oxazoline) ligands.
LIGAND-CONTROLLED C(SP3)-H ARYLATION AND OLEFINATION IN SYNTHESIS OF UNNATURAL CHIRAL ALPHA AMINO ACIDS
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Page/Page column 162; 163, (2015/10/05)
The use of ligands to tune the reactivity and selectivity of transition metal-catalysts for C(-sp3)-H bond functionalization is a central challenge in synthetic organic chemistry. Herein, we report a rare example of catalyst-controlled C(sp3)-H arylation using pyridine and quinoline derivatives: the former promotes exclusive monoarylation, whereas the latter activates the catalyst further to achieve diarylation. Successive application of these ligands enables the sequential diarylation of a methyl group in an alanine derivative with two different aryl iodides, affording a wide range of β-Ar-p-Ar ' -cc-amino acids with excellent levels of diastereoselectivity (d.r. > 20:1). Both configurations of the β-chiral center can be accessed by choosing the order in which the aryl groups are installed. The use of a quinoline derivative as a ligand also enables C(sp3)-H olefination of a protected alanine.
5-(α-fluorovinyl)-n-tosylindole
Gharat, Laxmikant A.,Martin, Arnold R.
, p. 185 - 189 (2007/10/02)
A α-fluorovinyl (or α-fluoroethene) substituent was introduced into the indole 5-position using an "atypical" Heck reaction. 5-Iodoindole (4) is preferred over 5-bromoindole as the starting material. Protection of the indole nitrogen is necessary.
