26767-06-6Relevant articles and documents
Direct 1,2-Dicarbonylation of Alkenes towards 1,4-Diketones via Photocatalysis
Chen, Bin,Cheng, Yuan-Yuan,Hou, Hong-Yu,Lei, Tao,Tung, Chen-Ho,Wu, Li-Zhu,Yu, Ji-Xin
supporting information, p. 26822 - 26828 (2021/11/17)
1,4-Dicarbonyl compounds are intriguing motifs and versatile precursors in numerous pharmaceutical molecules and bioactive natural compounds. Direct incorporation of two carbonyl groups into a double bond at both ends is straightforward, but also challenging. Represented herein is the first example of 1,2-dicarbonylation of alkenes by photocatalysis. Key to success is that N(n-Bu)4+ not only associates with the alkyl anion to avoid protonation, but also activates the α-keto acid to undergo electrophilic addition. The α-keto acid is employed both for acyl generation and electrophilic addition. By tuning the reductive and electrophilic ability of the acyl precursor, unsymmetric 1,4-dicarbonylation is achieved for the first time. This metal-free, redox-neutral and regioselective 1,2-dicarbonylation of alkenes is executed by a photocatalyst for versatile substrates under extremely mild conditions and shows great potential in biomolecular and drug molecular derivatization.
Diazotrifluoroethyl Radical: A CF3-Containing Building Block in [3 + 2] Cycloaddition
Zhao, Wen-Wen,Shao, Yong-Chao,Wang, An-Ni,Huang, Jia-Li,He, Chun-Yang,Cui, Bao-Dong,Wan, Nan-Wei,Chen, Yong-Zheng,Han, Wen-Yong
supporting information, p. 9256 - 9261 (2021/12/06)
We present herein a visible-light-induced [3 + 2] cycloaddition of a hypervalent iodine(III) reagent with α-ketoacids for the construction of 5-CF3-1,3,4-oxadiazoles that are of importance in medicinal chemistry. The reaction proceeds smoothly without a photocatalyst, metal, or additive under mild conditions. Different from the well-established trifluorodiazoethane (CF3CHN2), the diazotrifluoroethyl radical [CF3C(·)N2], a trifluoroethylcarbyne (CF3C?:) equivalent and an unusual CF3-containing building block, is involved in the present reaction system.
1D Fe3O4&at;CuSiO3 composites catalyzed decarboxylative A3-coupling for propargylamine synthesis
Cao, Tiantian,Feng, Huangdi,Li, Huiqiong,Miao, Teng,Wang, Fang,Zhang, Min
supporting information, p. 1558 - 1563 (2020/07/30)
Highly active and stable magnetic copper catalysts were successfully achieved by magnetic induced St?ber method and subsequent hydrothermal reaction with copper ions in alkaline condition. The high content of Cu2+ as well as the unique structures of hierarchical copper silicate in the as-prepared catalysts endowed their outstanding catalytic performance. Efficient decarboxylative A3-coupling of α-keto acid, amine and alkyne was realized with the low Fe3O4&at;CuSiO3 loading. A range of propargylamines were produced in good to excellent yields under solvent-free condition. Moreover, the catalyst can be easily separated from the final organic product with an external magnet. Also, this kind of catalyst could be recycled up to six times while maintaining its activity.
Selective photoredox decarboxylation of α-ketoacids to allylic ketones and 1,4-dicarbonyl compounds dependent on cobaloxime catalysis
Zhang, Hong,Xiao, Qian,Qi, Xu-Kuan,Gao, Xue-Wang,Tong, Qing-Xiao,Zhong, Jian-Ji
supporting information, p. 12530 - 12533 (2020/11/02)
A photoredox/cobaloxime co-catalyzed coupling reaction of α-ketoacids and methacrylates to obtain allylic ketones is described. Without the cobaloxime catalyst, 1,4-dicarbonyl compounds are generated. The cobaloxime catalyst enables dehydrogenation to generate the formation of new olefins. The generality, good substrate scope and mild conditions are good features in the photoredox/cobaloxime catalysis protocol, and this method will provide new opportunities for the functionalization of more olefins.
Metal-free benzoylation of imidazoheterocycles by oxidative decarboxylation of arylglyoxylic acids
Jaspal, Sonam,Shinde, Vikki N.,Meena, Neha,Nipate, Dhananjay S.,Rangan, Krishnan,Kumar, Anil
, p. 9072 - 9080 (2020/11/27)
A simple and straightforward approach has been realized for the direct benzoylation of imidazoheterocycles by oxidative decarboxylation of arylglyoxylic acids in the presence of K2S2O8 as an oxidant. Various functional groups were tolerated on both imidazoheterocycles and arylglyoxylic acids and a wide range of C5-benzoyl-imidazoheterocycles were obtained in good to high yields (50-84%). Radical trapping experiments confirmed the involvement of the radical pathway. The developed protocol is amenable for a scale-up reaction. This journal is
Photoredox Catalysis Enables Decarboxylative Cyclization with Hypervalent Iodine(III) Reagents: Access to 2,5-Disubstituted 1,3,4-Oxadiazoles
Li, Jian,Lu, Xue-Chen,Xu, Yue,Wen, Jin-Xia,Hou, Guo-Quan,Liu, Li
supporting information, p. 9621 - 9626 (2020/12/21)
A novel approach to 2,5-disubstituted 1,3,4-oxadiazoles derivatives via a decarboxylative cyclization reaction by photoredox catalysis between commercially available α-oxocarboxylic acids and hypervalent iodine(III) reagent is described. This powerful transformation involves the coupling reaction between two different kinds of radical species and the formation of C-N and C-O bonds.
Silver-catalyzed Double Decarboxylative Radical Alkynylation/Annulation of Arylpropiolic Acids with α-keto Acids: Access to Ynones and Flavones under Mild Conditions
Meng, Mengting,Wang, Guofang,Yang, Liangfeng,Cheng, Kai,Qi, Chenze
supporting information, p. 1218 - 1231 (2018/02/16)
Ynones are privileged building blocks in various organic syntheses of heterocyclic derivatives due to their multifunctional nature, and flavones are an important class of natural products with a wide range of biological activities. We describe the catalytic double decarboxylative alkynylation of arylpropiolic acids with α-keto acids. With Ag(I)/persulfate as the catalysis system, the valuable ynones bearing various substituents could be easily obtained. The introduction of hydroxyl substituent on ortho-site of α-keto acids make this strategy further applicable to the construction of flavone derivatives via heteroannulation in moderate to good yields with a similar silver-catalyzed system. The reactions proceed under relatively mild reaction conditions and tolerate a wide variety of functional groups. Control experiments indicated that both the reactions undergo radical processes. (Figure presented.).
Domino Synthesis of α,β-Unsaturated γ-Lactams by Stereoselective Amination of α-Tertiary Allylic Alcohols
Xie, Jianing,Xue, Sijing,Escudero-Adán, Eduardo C.,Kleij, Arjan W.
supporting information, p. 16727 - 16731 (2018/11/23)
Tertiary allylic alcohols equipped with a carboxyl group can be smoothly aminated under ambient conditions by a conceptually new and stereoselective protocol under palladium catalysis. The in situ formed Z-configured γ-amino acid cyclizes to afford an α,β-unsaturated γ-lactam, releasing water as the only byproduct. This practical catalytic transformation highlights the use of a carboxyl group acting as an activating and stereodirecting functional group to provide a wide series of pharma-relevant building blocks. Various control reactions support the crucial role of the carboxyl group in the substrate to mediate these transformations.
The Synthesis of Chiral α-Aryl α-Hydroxy Carboxylic Acids via RuPHOX-Ru Catalyzed Asymmetric Hydrogenation
Guo, Huan,Li, Jing,Liu, Delong,Zhang, Wanbin
supporting information, p. 3665 - 3673 (2017/09/11)
A ruthenocenyl phosphino-oxazoline-ruthenium complex (RuPHOX?Ru) catalyzed asymmetric hydrogenation of α-aryl keto acids has been successfully developed, affording the corresponding chiral α-aryl α-hydroxy carboxylic acids in high yields and with up to 97% ee. The reaction could be performed on a gram scale with a relatively low catalyst loading (up to 5000 S/C) and the resulting products can be transformed to several chiral building blocks, biologically active compounds and chiral drugs. (Figure presented.).
α-Keto Acids as Acylating Agents in the Synthesis of 2-Substituted Benzothiazoles and Benzoselenazoles
Lima, David B.,Penteado, Filipe,Vieira, Marcelo M.,Alves, Diego,Perin, Gelson,Santi, Claudio,Lenard?o, Eder J.
supporting information, p. 3830 - 3836 (2017/07/22)
Herein, we report the first decarboxylative oxidation of α-keto acids that is promoted by sodium metabisulfite (Na2S2O5) to obtain 2-substituted benzothiazoles and benzoselenazoles. Diaryl disulfides and diselenides were used as chalcogen sources, and the desired products were obtained in moderate to excellent yields. This protocol does not require an inert gas, transition metals, or harsh reaction conditions, and CO2 is released as an environmentally benign coproduct. The presence of Na2S2O5 was essential to guarantee that the reaction reached completion and afforded maximum product yields.
