37136-39-3Relevant academic research and scientific papers
Iron-Catalyzed Tertiary Alkylation of Terminal Alkynes with 1,3-Diesters via a Functionalized Alkyl Radical
Tian, Ming-Qing,Shen, Zhen-Yao,Zhao, Xuefei,Walsh, Patrick J.,Hu, Xu-Hong
supporting information, p. 9706 - 9711 (2021/03/19)
Direct oxidative C(sp)?H/C(sp3)?H cross-coupling offers an ideal and environmentally benign protocol for C(sp)?C(sp3) bond formations. As such, reactivity and site-selectivity with respect to C(sp3)?H bond cleavage have remained a persistent challenge. Herein is reported a simple method for iron-catalyzed/silver-mediated tertiary alkylation of terminal alkynes with readily available and versatile 1,3-dicarbonyl compounds. The reaction is suitable for an array of substrates and proceeds in a highly selective manner even employing alkanes containing other tertiary, benzylic, and C(sp3)?H bonds alpha to heteroatoms. Elaboration of the products enables the synthesis of a series of versatile building blocks. Control experiments implicate the in situ generation of a tertiary carbon-centered radical species.
Unnatural α-amino ethyl esters from diethyl malonate or ethyl β-bromo-α-hydroxyiminocarboxylate
Coutant, Eloi P.,Hervin, Vincent,Gagnot, Glwadys,Ford, Candice,Baatallah, Racha,Janin, Yves L.
supporting information, p. 2853 - 2860 (2018/11/26)
We have explored here the scope of the age-old diethyl malonate-based accesses to α-amino esters involving Knoevenagel condensations of diethyl malonate on aldehydes, reductions of the resulting alkylidenemalonates, the preparation of the corresponding α-hydroxyimino esters and their final reduction. This synthetic pathway turned out to be general although some unexpected limitations were encountered. The synthetic modifications of some of the intermediates - using Suzuki-Miyaura coupling or cycloadditions - before undertaking the oximation step - provided accesses to further α-amino esters. Moreover, other pathways to α-hydroxyimino esters were explored including an attempt to improve the cycloadditions between ethyl β-bromo-α-hydroxyiminocarboxylate and various alkylfuranes.
Palladium-Catalyzed Atom-Transfer Radical Cyclization at Remote Unactivated C(sp3)?H Sites: Hydrogen-Atom Transfer of Hybrid Vinyl Palladium Radical Intermediates
Ratushnyy, Maxim,Parasram, Marvin,Wang, Yang,Gevorgyan, Vladimir
supporting information, p. 2712 - 2715 (2018/03/02)
A novel mild, visible-light-induced palladium-catalyzed hydrogen atom translocation/atom-transfer radical cyclization (HAT/ATRC) cascade has been developed. This protocol involves a 1,5-HAT process of previously unknown hybrid vinyl palladium radical intermediates, thus leading to iodomethyl carbo- and heterocyclic structures.
Organocatalytic asymmetric direct Csp3 -H functionalization of ethers: A highly efficient approach to chiral spiroethers
Jiao, Zhi-Wei,Zhang, Shu-Yu,He, Chuan,Tu, Yong-Qiang,Wang, Shao-Hua,Zhang, Fu-Min,Zhang, Yong-Qiang,Li, Hui
supporting information; experimental part, p. 8811 - 8815 (2012/10/08)
Spiro compounds: An organocatalytic asymmetric method for the C sp 3=H functionalization of the α position of racemic cyclic ethers has been developed. The transformation, mediated by catalytic amounts of an imidazolidinone and strong acid, involves a tandem 1,5-hydride transfer/cyclization and provides access to a structurally diverse series of chiral spiroethers with high levels of enantioselectivity (see scheme). Copyright
Intermolecular atom transfer radical addition to olefins mediated by oxidative quenching of photoredox catalysts
Nguyen, John D.,Tucker, Joseph W.,Konieczynska, Marlena D.,Stephenson, Corey R. J.
supporting information; experimental part, p. 4160 - 4163 (2011/06/11)
Atom transfer radical addition of haloalkanes and α-halocarbonyls to olefins is efficiently performed with the photocatalyst Ir[(dF(CF 3)ppy)2(dtbbpy)]PF6. This protocol is characterized by excellent yields, mild conditions, low catalyst loading, and broad scope. In addition, the atom transfer protocol can be used to quickly and efficiently introduce vinyl trifluoromethyl groups to olefins and access 1,1-cyclopropane diesters.
Room temperature hydroalkylation of electron-deficient olefins: sp 3 C-H functionalization via a Lewis acid-catalyzed intramolecular redox event
Pastine, Stefan J.,McQuaid, Kevin M.,Sames, Dalibor
, p. 12180 - 12181 (2007/10/03)
A practical method for the intramolecular hydroalkylation of electron-deficient olefins has been developed. The direct transformation of benzylic, tertiary, and sterically hindered secondary sp3 C-H bonds into C-C bonds under the action of a catalytic amount of a variety of Lewis acids is described. The mechanism of these transformations is proposed to involve a tandem hydride transfer/cyclization sequence. Copyright
Room temperature intramolecular hydro-O-alkylation of aldehydes: sp 3 C-H functionalization via a lewis acid catalyzed tandem 1,5-hydride transfer/cyclization
Pastine, Stefan J.,Sames, Dalibor
, p. 5429 - 5431 (2007/10/03)
(Chemical Equation Presented) The scope and limitations of intramolecular hydro-O-alkylation of aldehyde substrates leading to spiroketals and bicyclic ketals and aminals is reported. The direct transformation of tertiary and sterically hindered secondary sp3 C-H bonds into C-O bonds under the action of a catalytic amount of a variety of Lewis acids is described. The mechanism of these transformations is proposed to involve a tandem hydride transfer/cyclization sequence.
2-DIETHYLAMINOETHYL ESTERS OF 1,3-DISUBSTITUTED PROPANE-2-CARBOXYLIC ACIDS
Valenta, Vladimir,Holubek, Jiri,Svatek, Emil,Miller, Vladimir,Vlkova, Marie,Protiva, Miroslav
, p. 2534 - 2544 (2007/10/02)
Alkaline hydrolysis of diethyl 1-(tetrahydro-2-furyl)-3-(1-naphthyl)propane-2,2-dicarboxylate (IV) gave the crude acid V which was purified via the dipotassium salt and was obtained as the homogenous higher melting crystal form.Its thermic decarboxylation yielded the acid II as a mixture of two racemates (38:62); crystallization led to almost homogenous racemate B (10:90).Reaction of the sodium salt of II with dimethyl sulfate in methanol gave the methyl ester III which afforded by ester exchange with 2-diethylaminoethanol the ester I (mixture of two racemates 34:66). 2-Diethylaminoethyl 1,3-bis(1-naphthyl)propane-2-carboxylate (VII) was synthetized in three steps from diethyl (1-naphthylmethyl)malonate.Ester X was obtained from 1,3-bis(tetrahydro-2-furyl)propane-2-carboxylic acid by treatment with 2-diethylaminoethyl chloride in boiling 2-propanol in the presence of potassium carbonate.The acid V gave similarly the diester VI. 2-Diethylaminoethyl esters I, VI, VII, and X were transformed to the hydrogen oxalates.Pharmacological screening showed for the diester VI hypotensive, spasmolytic, antiarrhythmic, and antitussic activity.
