- Chemodivergent Spirocyclization of 2-Sec-Aminobenzilidene Imidazolones: Lewis Versus Br?nsted Acids Catalysis
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Benzylidene imidazolones with ortho- secondary aminogroup undergo acid-promoted chemodivergent spirocyclization. Strong Lewis acids provide access to spirocyclic tetrahydroquinolines via [1,5]-hydride shift triggered cyclization despite of the presence of
- Baleeva, Nadezhda S.,Baranov, Mikhail S.,Gluschenko, Darya A.,Ivanov, Dmitrii S.,Mikhaylov, Andrey A.,Rustamova, Dina A.,Smirnov, Alexander Yu.,Sycheva, Maria A.,Zaitseva, Elvira R.
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p. 1587 - 1595
(2022/04/12)
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- Catalyst-free photodecarbonylation ofortho-amino benzaldehyde
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It is almost a consensus that decarbonylation of the aldehyde group (-CHO) needs to not only be mediated by transition metal catalysts, but also requires severe reaction conditions (high temperature and long reaction time). In this work, inspired by the “conformational-selectivity-based” design strategy, we broke this consensus and discovered a catalyst-free photodecarbonylation of the aldehyde group. It revealed that decarbonylation can be easily achieved with visible light irradiation by introducing a tertiary amine into theortho-position of the aldehyde group. A diverse array of tertiary amines is tolerated by our photodecarbonylation under mild conditions. Furthermore, the (QM) computations of the mechanism and the experiments on well-designed special substrates revealed that our photodecarbonylation depends on the conformational specificity of the aldehyde group and tertiary amine, and occurs through an unusual [1,4]-H shift and a subsequent [1,3]-H shift.
- Li, Lamei,Wang, Songping,Wei, Wentao,Yan, Ming,Zhou, Jingwei
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supporting information
p. 3421 - 3426
(2020/06/25)
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- Phosphine-Catalyzed Reaction between 2-Aminobenzaldehydes and Dialkyl Acetylenedicarboxylates: Synthesis of 1,2-Dihydroquinoline Derivatives and Toward the Development of an Olefination Reaction
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A series of 1,2-dihydroquinolines were synthesized in good to excellent yields by reacting 2-aminobenzaldehyde derivatives and dialkyl acetylenedicarboxylates with catalytic amounts of phosphine. This reaction was rendered catalytic by the selective in situ phosphine oxide reduction with the use of phenylsilane. Furthermore, with the same starting materials and with an additional role of the reducing agent, a new olefination reaction was discovered. Hydrogen/deuterium (H/D) exchange experiments revealed the possible mechanism of this reaction.
- Han, Xu,Saleh, Nidal,Retailleau, Pascal,Voituriez, Arnaud
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p. 4584 - 4588
(2018/08/09)
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- Fine-Tunable 3,4-dihydroquinazol-2-ylidene carbenes: Synthesis, rhodium(I) complexes, and reactivity
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The design and synthesis of various new six-membered cyclic formamidinium salts with a 3,4-dihydroquinazoline core have been reported in this paper. Our synthetic strategy allows access to a kind of tailor-made 3,4- dihydroquinazolinium salts bearing different substituent combinations. A series of novel 3,4-dihydroquinazolin-2-ylidene-based rhodium(I) complexes were prepared by the reaction of [Rh(cod)Cl]2 with the free carbene obtained in situ from the deprotonation of the corresponding 3,4-dihydroquinazolinium salts with KN(SiMe3)2. The NHCs prepared in situ can also react with S8 or CS2 to afford the corresponding thiones or NHC-CS2 adducts, respectively. The rhodium(I) complexes were transformed to the corresponding dicarbonyl complexes, and the ν(CO) values of the corresponding dicarbonyl Rh complexes indicate the 3,4-dihydroquinazol-2-ylidenes are stronger electron donors than normal five-membered NHCs. The Rh complexes are highly active in the arylation of carbonyl compounds, and the 3,4-dihydroquinazolin-2-ylidenes prepared in situ upon deprotonation are powerful in palladium-catalyzed Suzuki cross-coupling reactions at room temperature with a ppm scale catalyst loading with TONs of up to 425 000.
- Zhang, Jun,Qin, Xinke,Fu, Jun,Wang, Xiao,Su, Xiaolong,Hu, Fangle,Jiao, Jiajun,Shi, Min
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p. 8275 - 8282
(2013/02/22)
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- Two Component Recyclable Heterogeneous Catalyst, Process for Preparation Thereof and its Use for Preparation of Amines
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The invention describes the development of highly efficient, recyclable two component system, CuAl-hydrotalcite/rac 1,1′-Binaphthalene-2,2′-diol catalytic system for the N-alkylation of electron deficient aryl chlorides in presence of potassium carbonate as a base at room temperature in 3-6 h, wherein the process is provided for the preparation of various secondary amines via C—N coupling reaction of aliphatic amines(aliphatic open chain, acyclic, benzyl amines and heterocyclic amines) with various aryl chlorides.
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Page/Page column 5
(2012/01/13)
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- Application of daugulis copper-catalyzed direct arylation to the synthesis of 5-aryl benzotriazepines
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A method for the direct arylation of benzotriazepines is reported, employing an aryl iodide as the coupling partner, copper iodide as the catalyst, and lithium tert-butoxide as the base. A variety of electron-rich, electron-poor, and sterically hindered aryl iodides are compatible with the reaction conditions. The arylation reaction can also be performed outside a glovebox in air without a significant decrease in yield. Furthermore, convenient microwave conditions for carrying out this transformation are reported.
- Yotphan, Sirilata,Bergman, Robert G.,Ellman, Jonathan A.
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supporting information; experimental part
p. 1511 - 1514
(2009/08/07)
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