118334-83-1Relevant articles and documents
Electrochemical decarboxylative C3 alkylation of quinoxalin-2(1: H)-ones with N -hydroxyphthalimide esters
Niu, Kaikai,Song, Lingyun,Hao, Yanke,Liu, Yuxiu,Wang, Qingmin
, p. 11673 - 11676 (2020)
We have developed a protocol for electrochemical decarboxylative C3 alkylation of a wide range of quinoxalin-2(1H)-ones under metal- and additive-free conditions. N-Hydroxyphthalimide esters derived from chain, cyclic, primary, secondary, and tertiary carboxylic acids with a broad scope proved to be suitable substrates. This operationally simple protocol performed in an undivided cell under constant-current conditions is suitable for late-stage functionalization of quinoxalin-2(1H)-ones. The reactions can even be carried out with a 3 V battery as a power source, which demonstrates that organic electrosynthesis can be accomplished without the need for specialized equipment.
Constructing Quaternary Carbons from N -(Acyloxy)phthalimide Precursors of Tertiary Radicals Using Visible-Light Photocatalysis
Pratsch, Gerald,Lackner, Gregory L.,Overman, Larry E.
, p. 6025 - 6036 (2015)
Tertiary carbon radicals have notable utility for uniting complex carbon fragments with concomitant formation of new quaternary carbons. This article explores the scope, limitations, and certain mechanistic aspects of Okada's method for forming tertiary c
Copper-Catalyzed Decarboxylative Radical Silylation of Redox-Active Aliphatic Carboxylic Acid Derivatives
Xue, Weichao,Oestreich, Martin
, p. 11649 - 11652 (2017)
A decarboxylative silylation of aliphatic N-hydroxyphthalimide (NHPI) esters using Si?B reagents as silicon pronucleophiles is reported. This C(sp3)?Si cross-coupling is catalyzed by copper(I) and follows a radical mechanism, even with exclusion of light. Both primary and secondary alkyl groups couple effectively, whereas tertiary alkyl groups are probably too sterically hindered. The functional-group tolerance is generally excellent, and α-heteroatom-substituted substrates also participate well. This enables, for example, the synthesis of α-silylated amines starting from NHPI esters derived from α-amino acids. The new method extends the still limited number of C(sp3)?Si cross-couplings of unactivated alkyl electrophiles.
Phosphoric Acid Mediated Light-Induced Minisci C?H Alkylation of N-Heteroarenes
Jin, Songyang,Geng, Xinxin,Li, Yujun,Zheng, Ke
, p. 969 - 972 (2021)
Herein, we report an environmentally-friendly light-induced Minisci alkylation of N-heteroarenes with a broad substrate scope using diphenyl phosphate as catalyst under metal- and photocatalyst-free conditions. The radical precursor redox-active esters (R
Deprotonated Salicylaldehyde as Visible Light Photocatalyst
Zhuang, Yan-Jun,Qu, Jian-Ping,Kang, Yan-Biao
, p. 4386 - 4397 (2020)
Salicylaldehyde is established as an efficient visible light photocatalyst for the first time. Compared to other simple aldehyde analogies, salicylaldehyde has a unique deprotonative red-shift from 324 to 417 nm and gives rise to the remarkable increase of fluorescence quantum from 0.0368 to 0.4632, thus enabling salicylaldehyde as a visible light (>400 nm) photocatalyst. The experimental investigations suggest that the reactive radical species are generated by sensitization of the substrates by the deprotonated salicylaldehyde through an energy-transfer pathway. Consequently, the C-C cleaving alkylation reactions of N-hydroxyphthalimide esters proceed smoothly in the presence of as low as 1 mol % of salicylaldehyde under the visible-light irradiation, affording desired alkylation products with up to 99% yields. Application in visible-light induced aerobic oxidation of N-alkylpyridinium salts is also reported.
Metal-Free Photoinduced Hydroalkylation Cascade Enabled by an Electron-Donor-Acceptor Complex
Correia, José Tiago M.,Piva Da Silva, Gustavo,Kisukuri, Camila M.,André, Elias,Pires, Bruno,Carneiro, Pablo S.,Paixa?, Márcio W.
, p. 9820 - 9834 (2020)
A metal- A nd photocatalyst-free photoinduced radical cascade hydroalkylation of 1,7-enynes has been disclosed. The process is triggered by a single electron transfer (SET) event involving a photoexcited electron-donor-acceptor complex between an NHPI ester and a Hantzsch ester, which decomposes to afford a tertiary radical that is readily trapped by the enyne. The method provides an operationally simple, robust, and step-economical approach toward the construction of diversely functionalized dihydroquinolinones bearing quaternary centers. A sequential one-pot hydroalkylation-isomerization approach is also offered, giving access to a family of quinolinones. A wide substrate scope and high functional group tolerance were observed in both approaches.
Biocompatible Photoinduced Alkylation of Dehydroalanine for the Synthesis of Unnatural α-Amino Acids
Delgado, José A. C.,Correia, José T. M.,Pissinati, Emanuele F.,Paix?o, Márcio W.
, p. 5251 - 5255 (2021)
A site-selective alkylation of dehydroalanine to access protected unnatural amino acids is described. The protocol is characterized by the wide nature of alkyl radicals employed, mild conditions, and functional group compatibility. This protocol is further extended to access peptides, late-stage functionalization of pharmaceuticals, and enantioenriched amino acids.
Stereoselective and Divergent Construction of β-Thiolated/Selenolated Amino Acids via Photoredox-Catalyzed Asymmetric Giese Reaction
Chen, Huan,Wang, Ping,Wang, Siyao,Yin, Hongli,Zhang, Qiang,Zheng, Mengjie,Zhou, Qingqing
, p. 14201 - 14209 (2020)
Sulfur and selenium occupy a distinguished position in biology owing to their redox activities, high nucleophilicity, and acyl transfer capabilities. Thiolated/selenolated amino acids, including cysteine, selenocysteine, and their derivatives, play critic
Catalyst-free electrochemical decarboxylative cross-coupling of: N -hydroxyphthalimide esters and N-heteroarenes towards C(sp3)-C(sp2) bond formation
Liu, Yichang,Xue, Liwei,Shi, Biyin,Bu, Faxiang,Wang, Dan,Lu, Lijun,Shi, Renyi,Lei, Aiwen
, p. 14922 - 14925 (2019)
Cheap and widely available carboxylic acids are a class of ideal substrates to construct valuable compounds. As a candidate of decarboxylative reactions, the acid-based neutral N-hydroxyphthalimide ester undergoes a reductive decarboxylative process rather than a common oxidative decarboxylative process, which is a potential transformation mode for new reactions. In this work, we developed an electrochemical C(sp3)-C(sp2) coupling of N-hydroxyphthalimide esters and N-heteroarenes without any catalysts. Remarkably, this electrochemical protocol can not only be directly realised by carboxylic acids in a one-pot fashion, but also be scaled up using a continuous-flow reactor.
Catalyst-Free Decarboxylation of Carboxylic Acids and Deoxygenation of Alcohols by Electro-Induced Radical Formation
Chen, Xiaoping,Luo, Xiaosheng,Peng, Xiao,Guo, Jiaojiao,Zai, Jiantao,Wang, Ping
, p. 3226 - 3230 (2020)
Electro-induced reduction of redox active esters and N-phthalimidoyl oxalates derived from naturally abundant carboxylic acids and alcohols provides a sustainable and inexpensive approach to radical formation via undivided electrochemical cells. The resulting radicals are trapped by an electron-poor olefin or hydrogen atom source to furnish the Giese reaction or reductive decarboxylation products, respectively. A broad range of carboxylic acid (1°, 2°, and 3°) and alcohol (2° and 3°) derivatives are applicable in this catalyst-free reaction, which tolerated a diverse range of functional groups. This method features simple operation, is a sustainable platform, and has broad application.
