15796-82-4Relevant academic research and scientific papers
Shuttle arylation by Rh(I) catalyzed reversible carbon–carbon bond activation of unstrained alcohols
Lutz, Marius D.R.,Gasser, Valentina C.M.,Morandi, Bill
supporting information, p. 1108 - 1119 (2021/04/19)
The advent of transfer hydrogenation and borrowing hydrogen reactions paved the way to manipulate simple alcohols in previously unthinkable manners and circumvented the need for hydrogen gas. Analogously, transfer hydrocarbylation could greatly increase the versatility of tertiary alcohols. However, this reaction remains unexplored because of the challenges associated with the catalytic cleavage of unactivated C–C bonds. Herein, we report a rhodium(I)-catalyzed shuttle arylation cleaving the C(sp2)–C(sp3) bond in unstrained triaryl alcohols via a redox-neutral β-carbon elimination mechanism. A selective transfer hydrocarbylation of substituted (hetero)aryl groups from tertiary alcohols to ketones was realized, employing benign alcohols as latent C-nucleophiles. All preliminary mechanistic experiments support a reversible β-carbon elimination/migratory insertion mechanism. In a broader context, this novel reactivity offers a new platform for the manipulation of tertiary alcohols in catalysis.
Dual Nickel- And Photoredox-Catalyzed Reductive Cross-Coupling of Aryl Halides with Dichloromethane via a Radical Process
Xu, Tao,Xu, Wenhao,Zheng, Purui
supporting information, (2020/11/13)
The first catalytic strategy to harness a new chloromethane radical from dichloromethane under dual Ni/photoredox catalytic conditions has been developed. Compared with traditional two-electron reductive process associated with metallic reductants, this method via a single-electron approach can proceed under exceptionally mild conditions (visible light, ambient temperature, no strong base) and exhibits complementary reactivity patterns. It affords a broad scope of many functional groups, including alkenyl, which suffers cyclopropanation in previous routes. The diarylmethane-d2 compounds can be readily available with this transformation.
A palladium-catalyzed C-H functionalization route to ketones: Via the oxidative coupling of arenes with carbon monoxide
Arndtsen, Bruce A.,Kinney, R. Garrison,Levesque, Taleah M.
, p. 3104 - 3109 (2020/03/27)
We describe the development of a new palladium-catalyzed method to generate ketones via the oxidative coupling of two arenes and CO. This transformation is catalyzed by simple palladium salts, and is postulated to proceed via the conversion of arenes into high energy aroyl triflate electrophiles. Exploiting the latter can also allow the synthesis of unsymmetrical ketones from two different arenes.
Cercosporin-bioinspired selective photooxidation reactions under mild conditions
Li, Jia,Bao, Wenhao,Tang, Zhaocheng,Guo, Baodang,Zhang, Shiwei,Liu, Haili,Huang, Shuping,Zhang, Yan,Rao, Yijian
supporting information, p. 6073 - 6081 (2019/11/20)
The development of an efficient system for selective oxidation of organic compounds to generate more valuable compounds with molecular oxygen is a significant challenge in industrial chemistry. Bioinspired by the ability of naturally occurring perylenequinonoid pigments (PQPs) to generate reactive oxygen species (ROS) upon photoirradiation, here we report that cercosporin, one of the perylenequinonoid pigments, can function as a cost-effective and environmentally friendly photocatalyst for a wide range of selective oxidations, including benzylic C-H bonds to carbonyls, amines to aldehydes, and sulfides to sulfoxides. All of the representative reactions proceeded smoothly with high efficiency under mild conditions. Owing to the use of inexpensive metal-free visible light-driven photocatalyst produced from microbial fermentation with cheap glucose as the starting material and the ease of handling, we expect that this developed method will be particularly attractive for many more applications in synthetic transformation.
Method for preparing symmetric diarylketone through catalytic oxidative carbonylation
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Paragraph 0023; 0024; 0025; 0026; 0028, (2019/03/08)
The invention discloses a method for preparing symmetric diarylketone of a formula (I) as shown in the description. The method comprises the following steps: mixing arylboronic acid (II) (Ar-B(OH)2 (II)), a palladium catalyst, a promoter and an organic solvent in a reactor, introducing air and CO having a volume ratio of (7-19):1, reacting under the conditions of a pressure of 1-6 atm and a temperature of 30-80 DEG C for 8-16 hours, and performing after-treatment on the reaction solution, thereby obtaining the product symmetric diarylketone. According to the method disclosed by the invention,the air directly serves as an oxidizing agent to replace the O2 to be applied to oxidative carbonylation of the arylboronic acid, and the ratio of the air to CO is beyond an explosion limit. Therefore, the catalytic system is safe and economic. The palladium catalyst is small in dosage and simple in separation and can be recycled for several times. The method disclosed by the invention is mild inreaction condition, excellent in substrate suitability and high in yield.
Nickel-Catalyzed Molybdenum-Promoted Carbonylative Synthesis of Benzophenones
Peng, Jin-Bao,Wu, Fu-Peng,Li, Da,Qi, Xinxin,Ying, Jun,Wu, Xiao-Feng
, p. 6788 - 6792 (2018/06/04)
A nickel-catalyzed molybdenum-promoted carbonylative coupling reaction for the synthesis of benzophenones from aryl iodides has been developed. Various substituted diaryl ketones were synthesized in moderate to excellent yields under CO-gas-free conditions. A synergetic effect of both nickel and molybdenum has been observed, which is also responsible for the success of this transformation.
Palladium-Catalyzed Carbonylative Homocoupling of Aryl Iodides for the Synthesis of Symmetrical Diaryl Ketones with Formic Acid
Wu, Fu-Peng,Peng, Jin-Bao,Qi, Xinxin,Wu, Xiao-Feng
, p. 173 - 177 (2017/11/27)
A convenient method for the palladium-catalyzed carbonylative homocoupling of aryl iodides was developed. With formic acid as the CO source, various symmetrical diaryl ketones were synthesized in moderate to good yield in the presence of a palladium catalyst.
Electron Transfer Reactions: KO tBu (but not NaO tBu) Photoreduces Benzophenone under Activation by Visible Light
Nocera, Giuseppe,Young, Allan,Palumbo, Fabrizio,Emery, Katie J.,Coulthard, Graeme,McGuire, Thomas,Tuttle, Tell,Murphy, John A.
supporting information, p. 9751 - 9757 (2018/07/21)
Long-standing controversial reports of electron transfer from KOtBu to benzophenone have been investigated and resolved. The mismatch in the oxidation potential of KOtBu (+0.10 V vs SCE in DMF) and the first reduction potential of benzophenone (of many values cited in the literature, the least negative value is -1.31 V vs SCE in DMF), preclude direct electron transfer. Experimental and computational results now establish that a complex is formed between the two reagents, with the potassium ion providing the linkage, which markedly shifts the absorption spectrum to provide a tail in the visible light region. Photoactivation at room temperature by irradiation at defined wavelength (365 or 400 nm), or even by winter daylight, leads to the development of the blue color of the potassium salt of benzophenone ketyl, whereas no reaction is observed when the reaction mixture is maintained in darkness. So, no electron transfer occurs in the ground state. However, when photoexcited, electron transfer occurs within a complex formed from benzophenone and KOtBu. TDDFT studies match experimental findings and also define the electronic transition within the complex as n → π, originating on the butoxide oxygen. Computation and experiment also align in showing that this reaction is selective for KOtBu; no such effect occurs with NaOtBu, providing the first case where such alkali metal ion selectivity is rationalized in detail. Chemical evidence is provided for the photoactivated electron transfer from KOtBu to benzophenone: tert-butoxyl radicals are formed and undergo fragmentation to form (acetone and) methyl radicals, some of which are trapped by benzophenone. Likewise, when KOC(Et)3 is used in place of KOtBu, then ethylation of benzophenone is seen. Further evidence of electron transfer was seen when the reaction was conducted in benzene, in the presence of p-iodotoluene; this triggered BHAS coupling to form 4-methylbiphenyl in 74% yield.
Acenequinocumulenes: Lateral and Vertical π-Extended Analogues of Tetracyanoquinodimethane (TCNQ)
Gruber, Marco,Padberg, Kevin,Min, Jie,Waterloo, Andreas R.,Hampel, Frank,Maid, Harald,Ameri, Tayebeh,Brabec, Christoph J.,Tykwinski, Rik R.
, p. 17829 - 17835 (2017/11/27)
We have designed a series of molecules and developed synthetic methodology that allows for the inclusion of structural diversity along both the lateral and vertical axes of the basic TCNQ skeleton. In the lateral direction, benzoannulation extends the π-s
Synthesis of Symmetrical Diaryl Ketones by Cobalt-Catalyzed Reaction of Arylzinc Reagents with Ethyl Chloroformate
Rérat, Alice,Michon, Christophe,Agbossou-Niedercorn, Francine,Gosmini, Corinne
, p. 4554 - 4560 (2016/09/23)
Symmetrical diaryl ketones were prepared by a cross-coupling reaction between aryl bromides and ethyl chloroformate. This new method, which uses a catalyst composed of CoBr2and a bipyridine ligand along with readily available starting materials, allows for the synthesis of a variety of symmetrical diaryl ketones in moderate to excellent yields (37–99 %) under mild conditions. This reaction, in which ethyl chloroformate acts as a surrogate of carbon monoxide in the presence of cobalt and zinc, represents an interesting alternative to previously known approaches for the synthesis of diarylmethanones.
