4535-59-5Relevant academic research and scientific papers
Synthesis of 2,3,5,6-tetrasubstituted tetrahydropyrans via (3,5)-oxonium-ene reaction
Saha, Pipas,Bhunia, Anup,Saikia, Anil K.
, p. 2470 - 2481 (2012)
An efficient method for the synthesis of 2,3,5,6-tetrasubstituted tetrahydropyrans has been developed from the reaction of aldehydes and ethyl 2-(1-hydroxyalkyl/hydroxy(phenyl)methyl)-5-methylhex-4-enoate using (3,5)-oxonium-ene reaction promoted by boron
Iodine-Catalyzed Synthesis of Substituted Furans and Pyrans: Reaction Scope and Mechanistic Insights
Pace, Domenic P.,Robidas, Rapha?l,Tran, Uyen P. N.,Legault, Claude Y.,Nguyen, Thanh Vinh
, p. 8154 - 8171 (2021/06/28)
Substituted pyrans and furans are core structures found in a wide variety of natural products and biologically active compounds. Herein, we report a practical and mild catalytic method for the synthesis of substituted pyrans and furans using molecular iodine, a simple and inexpensive catalyst. The method described is performed under solvent-free conditions at an ambient temperature and atmosphere, thus offering a facile and practical alternative to currently available reaction protocols. A combination of experimental studies and density functional theory calculations revealed interesting mechanistic insights into this seemingly simple reaction.
Diastereoselective and Stereodivergent Synthesis of 2-Cinnamylpyrrolines Enabled by Photoredox-Catalyzed Iminoalkenylation of Alkenes
Shen, Xu,Huang, Congcong,Yuan, Xiang-Ai,Yu, Shouyun
supporting information, p. 9672 - 9679 (2021/03/16)
A photoredox-catalyzed iminoalkenylation of γ-alkenyl O-acyl oximes has been developed. Readily available alkenylboronic acids serve as alkenylation reagents, leading to densely functionalized pyrrolines. Both (E)- and (Z)-cinnamylpyrrolines are accessible depending on the reaction solvent. In dichloromethane, (E)-cinnamylpyrrolines are produced through a photoredox-mediated single-electron-transfer process. In tetrahydrofuran, (Z)-cinnamylpyrrolines are generated by photocatalytic contra-thermodynamic E-to-Z isomerization of (E)-cinnamylpyrrolines though an energy-transfer pathway. Two stereocenters are established with complete diastereoselectivity and only one diastereomer is isolated.
Radical Aza-Cyclization of α-Imino-oxy Acids for Synthesis of Alkene-Containing N-Heterocycles via Dual Cobaloxime and Photoredox Catalysis
Tu, Jia-Lin,Liu, Jia-Li,Tang, Wan,Su, Ma,Liu, Feng
, p. 1222 - 1226 (2020/02/15)
Nitrogen-containing heterocycles are prevalent in both naturally and synthetically bioactive molecules. We report herein an unprecedented protocol for radical aza-cyclization of α-imino-oxy acids with pendant alkenes via synergistic photoredox and cobaloxime catalysis. With or without alkenes as the intermolecular cross-coupling partners, the transformation provides a variety of corresponding alkene-containing dihydropyrrole products in satisfactory yields. In the presence of external alkenes, the tandem reaction generates E-selective coupling products with excellent chemo- and stereoselectivity.
Photoredox Synthesis of Arylhydroxylamines from Carboxylic Acids and Nitrosoarenes
Davies, Jacob,Angelini, Lucrezia,Alkhalifah, Mohammed A.,Sanz, Laia Malet,Sheikh, Nadeem S.,Leonori, Daniele
supporting information, p. 821 - 830 (2018/01/11)
Hydroxylamines are found in biologically active compounds and serve as building blocks for the preparation of nitrogen-containing molecules. Here the direct conversion of carboxylic acids into the corresponding alkylhydroxylamines using organo-photoredox catalysis is reported. The process relies in the generation of alkyl radicals via photoinduced oxidation-decarboxylation and their following reaction with nitrosoarenes. We have successfully applied this method to the late-stage modification of complex and biologically active acids and applied it in novel radical cascade processes.
Enantioselective and Diastereoselective Ir-Catalyzed Hydrogenation of α-Substituted β-Ketoesters via Dynamic Kinetic Resolution
Gu, Guoxian,Lu, Jiaxiang,Yu, Ouran,Wen, Jialin,Yin, Qin,Zhang, Xumu
supporting information, p. 1888 - 1892 (2018/04/16)
An iridium/f-amphol catalytic system for the enantioselective hydrogenation of α-substituted β-ketoesters via dynamic kinetic resolution is reported. The desired anti products were obtained in high yields (up to 98%) with good diastereoselectivity (up to 96:4 diastereometic ratio (dr)) and excellent enantioselectivity (up to >99% enantiomeric excess (ee)). A catalytic model is proposed to explain the stereoselectivity.
Photoredox Imino Functionalizations of Olefins
Davies, Jacob,Sheikh, Nadeem S.,Leonori, Daniele
, p. 13361 - 13365 (2017/10/17)
Shown herein is that polyfunctionalized nitrogen heterocycles can be easily prepared by a visible-light-mediated radical cascade process. This divergent strategy features the oxidative generation of iminyl radicals and subsequent cyclization/radical trapping, which allows the effective construction of highly functionalized heterocycles. The reactions proceed efficiently at room temperature, utilize an organic photocatalyst, use simple and readily available materials, and generate, in a single step, valuable building blocks that would be difficult to prepare by other methods.
Application and preparation method of Morusignin L and derivatives thereof
-
, (2016/10/09)
The invention discloses application and preparation method of Morusignin L and derivatives thereof. According to the invention, by employing a Morusignin L total synthesis technological route, or in a process of Morusignin L total synthesis, structure modification is carried out on Morusignin L by replacing a substituent of a reaction substrate, and then Morusignin L and a series of derivatives can be synthesized. The Morusignin L is a kind of important anti-tumor activity lead compounds, a compound source can be provided for anti-tumor activity screening by synthesis of the derivatives, and Morusignin L and a series of derivatives have important meaning for searching the novel anti-tumor activity lead compounds. The preparation method of Morusignin L and the derivatives thereof has the advantages that operation is simple, raw material synthesis is low in cost and easy to perform and can be carried out in various organic solvents, the stability in air is good, the application is wide, and compatibility for various substituents is good. The derivatives have certain inhibition capability for the tumor cells growth activity, and can be used as an antitumor drug or an antitumor drug lead compound.
Cyclization-endoperoxidation cascade reactions of dienes mediated by a pyrylium photoredox catalyst
Gesmundo, Nathan J.,Nicewicz, David A.
supporting information, p. 1272 - 1281 (2014/06/24)
Triarylpyrylium salts were employed as single electron photooxidants to catalyze a cyclization-endoperoxidation cascade of dienes. The transformation is presumed to proceed via the intermediacy of diene cation radicals. The nature of the diene component was investigated in this context to determine the structural requirements necessary for successful reactivity. Several unique endoperoxide structures were synthesized in yields up to 79%.
HETEROCYCLISATIONS INDUCED BY THALLIUM(III) ACETATE. EFFECT OF VARYING THE INTERNAL NUCLEOPHILE
Michael, Joseph P.,Nkwelo, Mluleki M.
, p. 2549 - 2560 (2007/10/02)
The stereochemistry of the 2,5-disubstituted tetrahydrofuran formed on treating 5-methyl-1-phenylhex-4-en-1-ol (6) with thallium(III) acetate in appropriate solvents has been established as trans by means of nuclear Overhauser experiments.Replacement of t
