59771-18-5Relevant academic research and scientific papers
Reactivity of benzylidene and alkylidenemalonates in radical addition mediated with dialkylzincs – An intriguing story
Lingua, Hugo,Dwadnia, Nejib,Siri, Didier,Bertrand, Michèle P.,Feray, Laurence
supporting information, p. 7507 - 7515 (2018/11/27)
Benzylidene- and alkylidenemalonates are extremely reactive radical acceptors in dialkylzinc-mediated radical additions. Theoretical investigations showed that the multi-step radical-polar crossover process should be highly exothermic. Not only the addition of the alkyl radical to the complexed substrate is enthalpically favored but what is more, the homolytic substitution at the metal leading to a zinc enolate should also be exothermic, even though it necessitates the cleavage of the C-Zn bond from the complexed α-alkoxycarbonyl radical intermediate. This work was undertaken to highlight the power of chelation in controlling the fate of this type of reaction. Much to our surprise, no unambiguous experimental evidence could be put forward to prove the formation of the expected zinc enolate intermediate. Additionally, benzylidenemalonates and their alkylidene analogues (although to a lesser extent) exhibit an intriguing behavior. The backward reaction (retro-addition) can be triggered at work-up depending upon experimental conditions.
Alkyl radical precursor and application thereof in establishing C-C bond
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Paragraph 0108; 0109; 0132, (2018/09/14)
The invention provides a precursor for generating an alkyl radical based on the visible light induction and a novel method for generating the radical. The alkyl sulfenamide is used as the radical precursor to generate the alkyl radical by virtue of the C-S bond cracking accelerated by the visible light, and then the alkyl radical is applied to the chemical reaction for establishing a C-C bond. Thereaction system has the characteristic of high efficiency, and has important scientific significance and application value for researching the novel C-C bond formation reaction, organic synthesis, drug synthesis and the like. In general, the invention provides a novel general method having practical application value. The thioalcohol (thioether) with rich resources is converted to a tool for derivating the alkyl radical.
A Desulfurative Strategy for the Generation of Alkyl Radicals Enabled by Visible-Light Photoredox Catalysis
Xue, Fei,Wang, Falu,Liu, Jiazhen,Di, Jiamei,Liao, Qi,Lu, Huifang,Zhu, Min,He, Liping,He, Huan,Zhang, Dan,Song, Hao,Liu, Xiao-Yu,Qin, Yong
supporting information, p. 6667 - 6671 (2018/06/11)
Herein, we present a new desulfurative method for generating primary, secondary, and tertiary alkyl radicals through visible-light photoredox catalysis. A process that involves the generation of N-centered radicals from sulfinamide intermediates, followed by subsequent fragmentation, is critical to forming the corresponding alkyl radical species. This strategy has been successfully applied to conjugate addition reactions that features mild reaction conditions, broad substrate scope (>60 examples), and good functional-group tolerance.
Stereocontrol in the intramolecular Buchner reaction of diazoketones
Maguire, Anita R.,Buckley, N. Rachael,O'Leary, Patrick,Ferguson, George
, p. 4077 - 4091 (2007/10/03)
Rhodium(II) acetate catalysed intramolecular Buchner cyclisation of a series of diazoketones 1 proceeds with excellent diastereoselectivity to produce the trans substituted azulenones 2, which exist as a rapidly equilibrating cycloheptatriene-norcaradiene system, from which the norcaradiene tautomers can be efficiently trapped as PTAD cycloadducts 4. The cyclisation-cycloaddition sequence can be conducted in either a stepwise or a tandem process, leading to the pentacyclic systems 4 as a single diastereomer in each case. In the reaction of diazoketone If intramolecular cyclopropanation competes with cyclisation to the aromatic ring.
Remarkable dependence of the regioselectivity of free radical additions to 3-cinnamoyloxazolidin-2-ones on the stability of the intermediate adduct-radical, electrophilicity of the adding radicals and the conditions for their generation
Tararov, Vitali I.,Kuznetzov, Nikolai Yu.,Bakhmutov, Vladimir I.,Ikonnikov, Nikolai S.,Bubnov, Yuri N.,Khrustalev, Victor N.,Saveleva, Tatiana F.,Belokon, Yuri N.
, p. 3101 - 3106 (2007/10/03)
Electrophilic (CCl3) and nucleophilic radicals (Pri) are found to add at 80°C to the C=C bond of 3-(E)-cinnamoyl-4-phenyloxazolidin-2-one 1a and 3-(E)-cinnamoyl-4-benzyloxazolidin-2-one 1b predominantly at the α-position of the bond. While for the CCl3 radical no product of β-addition has been found, for the Pri radical such a path constitutes up to 40% of the whole process at 80°C. An interplay between the stability of the intermediate adduct radicals and the electrophilicity or nucleophilicity of the radicals undergoing addition are invoked to rationalize the observation. At a low temperature (-23°C) β-addition of the Pri radical becomes the dominant process (up to 75%).
