27356-87-2Relevant academic research and scientific papers
Electrochemical-induced radical allylation via the fragmentation of alkyl 1,4-dihydropyridines
Chen, Xiaoping,Luo, Xiaosheng,Wang, Ping
, (2022/02/02)
Aldehydes are abundant chemical motifs presented in natural products and pharmaceuticals. As a radical precursor, its application is limited. Dihydropyridines (DHPs) can act as masked aldehydes, providing alkyl radicals under the activation of Lewis acid, heat, SET oxidant and light irradiation. Herein, we report the direct activation of 4-alkyl DHPs via single electron transfer at the anode. C–C bond homolysis at the C4-position of DHP generated the corresponding alkyl radical, which was captured subsequently by 2-phenyl and 2-ethoxy carbonyl allyl bromide. The following intramolecular elimination reaction afforded 20 different radical allylation products bearing various alkyl substituents with yields up to 92%.
Silver-catalyzed decarboxylative radical allylation of α,α-difluoroarylacetic acids for the construction of CF2-allyl bonds
Wang, Pingyang,Du, Pengcheng,Sun, Qianqian,Zhang, Jianhua,Deng, Hongmei,Jiang, Haizhen
, p. 2023 - 2029 (2021/03/16)
An efficient silver-catalyzed method of decarboxylative radical allylation of α,α-difluoroarylacetic acids to build CF2-allyl bonds has been developed. Using allylsulfone as an allyl donor, α,α-difluorine substituted arylacetic acids bearing various functional groups are successfully allylated to access a series of 3-(α,α-difluorobenzyl)-1-propylene compounds in moderate to excellent yields in aqueous CH3CN solution under the mild conditions. Experimental studies disclosed that the α-fluorine substitution of arylacetic acid has a great influence on free radical activity and reactivity.
Alkylation of Allyl/Alkenyl Sulfones by Deoxygenation of Alkoxyl Radicals
Han, Jia-Bin,Guo, Ao,Tang, Xiang-Ying
supporting information, p. 2989 - 2994 (2019/02/05)
A challenging deoxygenation of alkoxyl radicals from readily accessible alcohol derivatives was developed, affording facile synthesis of functionalized alkenes with good functional group tolerance under mild reaction conditions. Because alkoxyl radicals can easily undergo β-fragmentations or hydrogen abstractions, this new strategy for deoxygenation of alkoxyl radicals is highly valuable. Moreover, mechanistic studies revealed that the electron-neutral phosphine acts as the deoxygenation reagent.
Donor–Acceptor Complex Enables Alkoxyl Radical Generation for Metal-Free C(sp3)–C(sp3) Cleavage and Allylation/Alkenylation
Zhang, Jing,Li, Yang,Xu, Ruoyu,Chen, Yiyun
, p. 12619 - 12623 (2017/09/11)
The alkoxyl radical is an essential and prevalent reactive intermediate for chemical and biological studies. Here we report the first donor–acceptor complex-enabled alkoxyl radical generation under metal-free reaction conditions induced by visible light. Hantzsch ester forms the key donor–acceptor complex with N-alkoxyl derivatives, which is elucidated by a series of spectrometry and mechanistic experiments. Selective C(sp3)-C(sp3) bond cleavage and allylation/alkenylation is demonstrated for the first time using this photocatalyst-free approach with linear primary, secondary, and tertiary alkoxyl radicals.
Silicates as Latent Alkyl Radical Precursors: Visible-Light Photocatalytic Oxidation of Hypervalent Bis-Catecholato Silicon Compounds
Corcé, Vincent,Chamoreau, Lise-Marie,Derat, Etienne,Goddard, Jean-Philippe,Ollivier, Cyril,Fensterbank, Louis
, p. 11414 - 11418 (2015/10/12)
This works introduces hypervalent bis-catecholato silicon compounds as versatile sources of alkyl radicals upon visible-light photocatalysis. Using Ir[(dF(CF3)ppy)2(bpy)](PF6) (dF(CF3)ppy=2-(2,4-difluorophenyl)-5-trifluoromethylpyridine, bpy=bipyridine) as catalytic photooxidant, a series of alkyl radicals, including highly reactive primary ones can be generated and engaged in various intermolecular homolytic reactions. Based on cyclic voltammetry, Stern-Volmer studies, and supported by calculations, a mechanism involving a single-electron transfer from the silicate to the photoactivated iridium complex has been proposed. This oxidative photocatalyzed process can be efficiently merged with nickel-catalyzed Csp2-Csp3 cross-coupling reactions.
Effect of Lewis acids and low temperature initiators on the allyl transfer reaction involving phthalimido-N-oxyl radical
Patil, Shradha,Chen, Liang,Tanko, James M.
, p. 7029 - 7033 (2015/01/09)
Previously, we reported allyl transfer reactions of allyl bromide and allyl phthalimido-N-oxyl substrates with hydrocarbons that result in CC bond formation. In both cases, efficient chain transfer processes along with high reaction yields were observed. Since PINO chemistry leads to an environmentally friendly method of hydrocarbon functionalization, additional studies were performed in order to improve the process. To expand the utility of this reaction, we carried out experiments to optimize reaction conditions and tested the effect of Lewis acids and low temperature initiators. Although allyl-PINO substrates reacted slightly slower than the bromides, the reactions were cleaner with little or no side products. The chain lengths for these reactions were compromised at lower temperatures, attributable to the high activation energy required for the hydrogen atom abstraction by PINO. The addition of a Lewis acid catalyst (AlCl3) improves the product yield and reaction rate, possibly due to the formation of a PINO/AlCl3 complex which lowers the activation energy for hydrogen abstraction step.
C-H Bond Functionalization with the Formation of a C-C Bond: A Free Radical Condensation Reaction Based on the Phthalimido-N-oxyl Radical
Patil, Shradha,Chen, Liang,Tanko, James M.
, p. 502 - 505 (2015/10/05)
The development of a new chemical process that effects the conversion RH + C=C-C-X → R-C-C=C + HX, in which X is the phthalimido-N-oxyl radical (PINO·), is reported. The reaction yields are high, mass balances are excellent, and C-H bond functionalization and C-C bond formation are achieved in a single transformation. The byproduct of the reaction, N-hydroxyphthalimide, precipitates from solution and can be easily removed by simple filtration (and recycled). The kinetic chain lengths are shorter and the reaction times are longer (relative to those of the analogous reactions of allyl bromides), most likely because PINO· is a less-reactive hydrogen-atom abstractor. There appears to be no significant difference in efficiency in the addition-elimination steps. Competition experiments reveal that Br· and PINO· are comparable in leaving group ability.
C-H bond functionalization with the formation of a C-C bond: A free radical condensation reaction based on the phthalimido-N-oxyl radical
Patil, Shradha,Chen, Liang,Tanko, James M.
, p. 502 - 505 (2014/02/14)
The development of a new chemical process that effects the conversion RH + C=C-C-X → R-C-C=C + HX, in which X is the phthalimido-N-oxyl radical (PINO·), is reported. The reaction yields are high, mass balances are excellent, and C-H bond functionalization and C-C bond formation are achieved in a single transformation. The byproduct of the reaction, N-hydroxyphthalimide, precipitates from solution and can be easily removed by simple filtration (and recycled). The kinetic chain lengths are shorter and the reaction times are longer (relative to those of the analogous reactions of allyl bromides), most likely because PINO· is a less-reactive hydrogen-atom abstractor. There appears to be no significant difference in efficiency in the addition-elimination steps. Competition experiments reveal that Br· and PINO· are comparable in leaving group ability. The introduction of a new chain carrier, the phthalimido-N-oxyl radical (PINO·), leads to an improved chain reaction. This chain reaction is successful and high reaction yields are reported for the functionalization of hydrocarbons. Kinetic studies reveal that this reaction is an efficient chain process, and the leaving group ability of PINO · is comparable to that of Br·. Copyright
Radical additions to allyl bromides. A synthetically useful, 'Tin-Free' method for carbon-carbon bond formation
Struss, John A.,Sadeghipour, Mitra,Tanko, James M.
supporting information; scheme or table, p. 2119 - 2120 (2009/07/19)
The scope and limitations of a novel free radical chain process involving the addition of benzyl radicals to substituted allyl bromides were examined and extended to explore the effect of α-substitution on the allyl bromide (R′), and the use of pyrrolidine amides and oxazolidinone as activating substituents (Z) as the first steps toward the development of a stereoselective, radical-based C-C bond-forming reaction which is environmentally benign.
α-Substituted norstatines as the transition-state mimic in inhibitors of multiple digestive vacuole malaria aspartic proteases
Orrling, Kristina M.,Marzahn, Melissa R.,Gutierrez-de-Teran, Hugo,Aqvist, Johan,Dunn, Ben M.,Larhed, Mats
experimental part, p. 5933 - 5949 (2009/12/24)
The impact of moving the P1 side-chain from the β-position to the α-position in norstatine-containing plasmepsin inhibitors was investigated, generating two new classes of tertiary alcohol-comprising α-benzylnorstatines and α-phenylnorstatines. Twelve α-s
