2001-23-2Relevant articles and documents
H2O2-mediated room temperature synthesis of 2-arylacetophenones from arylhydrazines and vinyl azides in water
Luo, Mengqiang,Zhang, Yaohong,Fang, Ping,Li, Yan,Qi, Chenze,Li, Yong,Shen, Runpu,Cheng, Kai,Wang, Hai
supporting information, p. 630 - 635 (2022/02/01)
An environmentally benign, cost-efficient and practical methodology for the room temperature synthesis of 2-arylacetophenones in water has been discovered. The facile and efficient transformation involves the oxidative radical addition of arylhydrazines with α-aryl vinyl azides in the presence of H2O2 (as a radical initiator) and PEG-800 (as a phase-transfer catalyst). From the viewpoint of green chemistry and organic synthesis, the present protocol is of great significance because of using cheap, non-toxic and readily available starting materials and reagents as well as amenability to gram-scale synthesis, which provides an attractive strategy to access 2-arylacetophenones.
Palladium-catalyzed denitrative α-arylation of ketones with nitroarenes
Li, Zhirong,Peng, Yonggang,Wu, Tao
supporting information, (2021/02/16)
The palladium-catalyzed α-arylation of ketones with readily available nitroarenes and nitroheteroarenes provides access to useful α-aryl and α-heteroaryl ketones. The use of the Pd/ BrettPhos catalysts was critical to achieve high efficiency for these transformations, whereas other catalysts led to decreased yields or no conversions. The intramolecular type substrate was also applied in this methodology and gave a chromone derivative. Polyaromatic carbonyl compounds can be easily obtained by multicomponent tandem reactions, via nucleophilic aromatic substitution (SNAr) or cross-coupling reaction followed by this denitrative arylation. Kinetic experiments show that the electronic effect of nitrobenzenes has a greater effect on the reaction rate than the electronic effect of ketones.
Benzylic Aroylation of Toluenes Mediated by a LiN(SiMe3)2/Cs+System
Dai, Ziteng,Gu, Yuanyun,Li, Jie,Mao, Jianyou,Walsh, Patrick J.,Wang, Yan-En,Xiong, Dan,Yuan, Yaqi,Zhang, Zhen
supporting information, (2022/01/14)
Chemoselective deprotonative functionalization of benzylic C-H bonds is challenging, because the arene ring contains multiple aromatic C(sp2)-H bonds, which can be competitively deprotonated and lead to selectivity issues. Recently it was found that bimetallic [MN(SiMe3)2 M = Li, Na]/Cs+ combinations exhibit excellent benzylic selectivity. Herein, is reported the first deprotonative addition of toluenes to Weinreb amides mediated by LiN(SiMe3)2/CsF for the synthesis of a diverse array of 2-arylacetophenones. Surprisingly, simple methyl benzoates also react with toluenes under similar conditions to form 2-arylacetophenones without double addition to give tertiary alcohol products. This finding greatly increases the practicality and impact of this chemistry. Some challenging substrates with respect to benzylic deprotonations, such as fluoro and methoxy substituted toluenes, are selectively transformed to 2-aryl acetophenones. The value of benzylic deprotonation of 3-fluorotoluene is demonstrated by the synthesis of a key intermediate in the preparation of Polmacoxib.
Benzylic aroylation of toluenes with unactivated tertiary benzamides promoted by directed ortho-lithiation
Bao, Can-Can,Luo, Yan-Long,Du, Hui-Zhen,Guan, Bing-Tao
, p. 1349 - 1354 (2021/07/12)
The deprotonative functionalization of toluenes, for their weak acidity, generally needs strong bases, thus leading to the requirement of harsh conditions and the generation of by-products. Direct nucleophilic acyl substitution reaction of amides with organometallic reagents could provide an ideal solution for ketone synthesis. However, the inert amides and highly reactive organometallic reagents bring great challenges for an efficient and selective synthetic approach. Herein, we reported an lithium diisopropylamide (LDA)-promoted benzylic aroylation of toluenes with unactivated tertiary benzamides, providing a direct and efficient synthesis of various aryl benzyl ketones. This process features a kinetic deprotonative functionalization of toluenes with a readily available base LDA. Mechanism studies revealed that the directed ortho-lithiation of the tertiary benzamide with LDA promoted the benzylic kinetic deprotonation of toluene and triggered the nucleophilic acyl substitution reaction with the amide. [Figure not available: see fulltext.].
1,2-Aryl Migration Induced by Amide C?N Bond-Formation: Reaction of Alkyl Aryl Ketones with Primary Amines Towards α,α-Diaryl β,γ-Unsaturated γ-Lactams
Hu, Rong,Tao, Yigao,Zhang, Xiaofeng,Su, Weiping
supporting information, p. 8425 - 8430 (2021/03/16)
Rearrangement reactions incorporated into cascade reactions play an important role in rapidly increasing molecular complexity from readily available starting materials. Reported here is a Cu-catalyzed cascade reaction of α-(hetero)aryl-substituted alkyl (hetero)aryl ketones with primary amines that incorporates an unusual 1,2-aryl migration induced by amide C?N bond formation to produce a class of structurally novel α,α-diaryl β,γ-unsaturated γ-lactams in generally good-to-excellent yields. This cascade reaction has a broad substrate scope with respect to primary amines, allows a wide spectrum of (hetero)aryl groups to smoothly undergo 1,2-migration, and tolerates electronically diverse α-substituents on the (hetero)aryl ring of the ketones. Mechanistically, this 1,2-aryl migration may stem from the intramolecular amide C?N bond formation which induces nucleophilic migration of the aryl group from the acyl carbon center to the electrophilic carbon center that is conjugated with the resulting iminium moiety.
Cobalt(II)-Catalyzed Stereoselective Olefin Isomerization: Facile Access to Acyclic Trisubstituted Alkenes
Zhang, Sheng,Bedi, Deepika,Cheng, Lu,Unruh, Daniel K.,Li, Guigen,Findlater, Michael
supporting information, p. 8910 - 8917 (2020/12/23)
Stereoselective synthesis of trisubstituted alkenes is a long-standing challenge in organic chemistry, due to the small energy differences between E and Z isomers of trisubstituted alkenes (compared with 1,2-disubstituted alkenes). Transition metal-catalyzed isomerization of 1,1-disubstituted alkenes can serve as an alternative approach to trisubstituted alkenes, but it remains underdeveloped owing to issues relating to reaction efficiency and stereoselectivity. Here we show that a novel cobalt catalyst can overcome these challenges to provide an efficient and stereoselective access to a broad range of trisubstituted alkenes. This protocol is compatible with both mono- and dienes and exhibits a good functional group tolerance and scalability. Moreover, it has proven to be a useful tool to construct organic luminophores and a deuterated trisubstituted alkene. A preliminary study of the mechanism suggests that a cobalt-hydride pathway is involved in the reaction. The high stereoselectivity of the reaction is attributed to both a π-πstacking effect and the steric hindrance between substrate and catalyst.
Nickel-catalyzed Kumada reaction of tosylalkanes with Grignard reagents to produce alkenes and modified arylketones
Wu, Ji-Cheng,Gong, Lu-Bing,Xia, Yuanzhi,Song, Ren-Jie,Xie, Ye-Xiang,Li, Jin-Heng
supporting information, p. 9909 - 9913 (2012/10/30)
Open a new door: The first example of alkene synthesis from alkyl electrophiles with Grignard reagents using the Kumada cross-coupling reaction strategy is reported. This method opens a new door for the Kumada cross-coupling reaction, allowing alkenes to be prepared from the reaction of tosylalkanes with Grignard reagents. Copyright
Arylation of α-pivaloxyl ketones with arylboronic reagents via Ni-catalyzed sp3 C-O activation
Huang, Kun,Li, Gang,Huang, Wei-Ping,Yu, Da-Gang,Shi, Zhang-Jie
, p. 7224 - 7226 (2011/08/09)
A Suzuki-Miyaura coupling of α-pivaloxyl ketones via Ni-catalyzed sp3 C-O activation to produce α-aryl ketones is developed. This study offers a convenient method to construct α-arylation products from readily available α-hydroxyl carbonyl compounds.
NOVEL DIHYDROPYRIMIDIN-2(1H)-ONE COMPOUNDS AS S-NITROSOGLUTATHIONE REDUCTASE INHIBITORS
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Page/Page column 140, (2011/04/24)
The present invention is directed to novel dihydropyrimidin-2(1H)-one compounds useful as S-nitrosoglutathione reductase (GSNOR) inhibitors, pharmaceutical compositions comprising such compounds, and methods of making and using the same.
A high speed parallel synthesis of 1,2-diaryl-1-ethanones via a clean-chemistry C-C bond formation reaction
Veeramaneni, Venugopal Rao,Pal, Manojit,Yeleswarapu, Koteswar Rao
, p. 3283 - 3290 (2007/10/03)
In this report, we describe the parallel as well as conventional synthesis of 1,2-diaryl-1-ethanones via environmentally benign acylation of arenes with in situ generated arylacetyl trifluoroacetates. A wide variety of arylacetic acids I participated in trifluoroacetic anhydride/phosphoric acid mediated C-C bond formation reaction when reacted with arenes of type II to give 1,2-diaryl-1-ethanones III in good to excellent yield. Under the solvent-free conditions these chemical transformations that normally require longer reaction time can be performed within minutes in good yield.
