- Iron-Catalyzed Ring Expansion of Cyclobutanols for the Synthesis of 1-Pyrrolines by Using MsONH3OTf
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The synthesis of 1-pyrrolines from cyclobutanol derivatives and an aminating reagent (MsONH3OTf) has been developed. This one-pot procedure achieves C–N bond/C═N bond formation via ring expansion. A series of 1-pyrroline derivatives are synthes
- Zhuang, Daijiao,Gatera, Tharcisse,An, Zhenyu,Yan, Rulong
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supporting information
p. 771 - 775
(2022/01/20)
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- Synthesis of 1-Pyrroline by Denitrogenative Ring Expansion of Cyclobutyl Azides under Thermal Conditions
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We herein report an efficient and systematic synthesis of 1-pyrrolines from cyclobutyl azides under thermal and neutral conditions. The reaction proceeded without any additional reagents, and nitrogen was generated as the sole by-product. Furthermore, the generated 1-pyrrolines could be continuously transformed into pyrroles, N-Boc-amines, and oxaziridines in an one-pot manner. (Figure presented.).
- Ban, Kazuho,Miki, Yuya,Sajiki, Hironao,Sawama, Yoshinari,Tomita, Naohito
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p. 3481 - 3484
(2021/06/17)
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- Intramolecular Csp3-H/C-C bond amination of alkyl azides for the selective synthesis of cyclic imines and tertiary amines
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The intramolecular Csp3-H and/or C-C bond amination is very important in modern organic synthesis due to its efficiency in the construction of diversified N-heterocycles. Herein, we report a novel intramolecular cyclization of alkyl azides for the synthesis of cyclic imines and tertiary amines through selective Csp3-H and/or C-C bond cleavage. Two C-N single bonds or a CN double bond are efficiently constructed in these transformations. The carbocation mechanism differs from the reported metal nitrene intermediates and therefore enables metal-free and new transformation.
- Jiao, Ning,Li, Xinyao,Luo, Xiao,Song, Song,Wang, Weijin,Wen, Xiaojin
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p. 4482 - 4487
(2020/05/18)
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- Enantioselective Imine Reduction Catalyzed by Phosphenium Ions
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The first use of phosphenium cations in asymmetric catalysis is reported. A diazaphosphenium triflate, prepared in two or three steps on a multigram scale from commercially available materials, catalyzes the hydroboration or hydrosilylation of cyclic imin
- Lundrigan, Travis,Welsh, Erin N.,Hynes, Toren,Tien, Chieh-Hung,Adams, Matt R.,Roy, Kayelani R.,Robertson, Katherine N.,Speed, Alexander W. H.
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supporting information
p. 14083 - 14088
(2019/10/11)
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- Highly effective asymmetric hydrogenation of cyclic N -alkyl imines with chiral cationic Ru-MsDPEN catalysts
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A range of cyclic N-alkyl imines were efficiently hydrogenated by using a chiral cationic Ru(η6-cymene)(MsDPEN)(BArF) complex (MsDPEN = N-(methanesulfonyl)-1,2-diphenylethylenediamine) in high yields and up to 98% ee. A one-pot synthesis of chiral 2-phenylpyrrolidine via reductive amination was also developed.
- Chen, Fei,Ding, Ziyuan,Qin, Jie,Wang, Tianli,He, Yanmei,Fan, Qing-Hua
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supporting information; experimental part
p. 4348 - 4351
(2011/10/13)
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- The reaction of cyclic imines with the Ruppert-Prakash reagent. Facile approach to α-trifluoromethylated nornicotine, anabazine, and homoanabazine
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We have demonstrated that the Ruppert-Prakash reagent is able to react with a number of cyclic imines under acidic condition to afford the corresponding α-trifluoromethyl derivatives of nitrogen heterocycles. 5-7-Membered cyclic imines bearing various alkyl, aryl or heterocyclic group were successfully involved in this transformation. Novel trifluoromethylated analogues of nicotine, anabasine, and homoanabasine alkaloids were synthesized.
- Shevchenko, Nikolay E.,Vlasov, Katja,Nenajdenko, Valentine G.,R?schenthaler, Gerd-Volker
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scheme or table
p. 69 - 74
(2011/02/27)
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- Reactions of cyclopropyl aryl ketones with sulfonamides mediated by Zr(OTf)4: Cascade preparation of 5-aryl-3,4-dihydro-2H-pyrrole
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We found that the Lewis acid Zr(OTf)4 can effectively promote the ring-opening reaction of cyclopropyl aryl ketones with sulfonamides. By controlling the reaction conditions, we could obtain the ring-opened products 3 and the cyclized products 5 in moderate to good yields. This process provides a novel and efficient route for the synthesis of 5-aryl-3,4-dihydro-2H-pyrrole in the presence of a Lewis acid.
- Shi, Min,Yang, Yong-Hua,Xu, Bo
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p. 1622 - 1624
(2007/10/03)
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- Oxidative C-arylation of free (NH)-heterocycles via direct (sp3) C-H bond functionalization
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The development of a new chemical transformation, namely oxidative C-arylation of saturated (NH)-heterocycles, is described. This reaction combines dehydrogenation and arylation in one process, leading to cross-coupling of (NH)-heterocycles and haloarenes. Typical reaction conditions involve heating the reaction partners in anhydrous dioxane at 120-150 °C in the presence of RhCl(CO)[P(Fur)3]2 as the catalyst and Cs2CO3 as the base. Addition of tert-butylethylene as the hydrogen acceptor increases the chemical yield by diminishing the dehalogenation pathway. This method demonstrated a good substrate scope, allowing for cross-coupling of a variety of (NH)-heterocycles (e.g., pyrrolidine, piperidine, piperazine, morpholine) and halo(hetero)arenes to afford valuable heterocyclic products in one step. The preliminary mechanistic studies provided some insight regarding the key events in the proposed catalytic cycle, including β-hydride elimination of an amido rhodium complex and carbometalation of the resulting imine. A large kinetic isotope effect [KIE (kC-H/kC-D) = 4.3] suggests that one or both β-hydride elimination steps are rate determining. The central role for the phosphine ligand was established in controlling the partitioning between the oxidative C-arylation and N-arylation pathways. Copyright
- Sezen, Bengue,Sames, Dalibor
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p. 13244 - 13246
(2007/10/03)
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- Convenient synthesis of melatonin analogues: 2- and 3-substituted -N-acetylindolylalkylamines
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A new method for the synthesis of 2- and 3-substituted indolylalkylamides, derivatives of melatonin, from arylhydrazines and amidoketones by the Fischer reaction was elaborated. The amidoketones can be easily prepared from cyclic imines by reaction with acylpyridinium chloride. This method is a one-step synchronous creation of the selected alkylamide fragment and the indole core. Variation of the arylhydrazines create the desired substituents in the carbocycle of indolylalkylamides and suitable choice of amidoketone can direct the amidoalkyl chain to the 2- or 3-position of the indole. Graphical Abstract
- Nenajdenko, Valentine G.,Zakurdaev, Eugene P.,Prusov, Eugene V.,Balenkova, Elizabeth S.
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p. 11719 - 11724
(2007/10/03)
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- Easy one-pot access to substituted 2-phenylpyrrolines from 2-pyrrolidinone
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An easy access to 2-aryl pyrrolidines is the reduction, stereospecific or not, of the corresponding 2-aryl-pyrroline (5-aryl-3,4-dihydro-2H-pyrrole). Preparation of the latter has been carried out from 2-pyrrolidinone using an easy one-pot two-step method
- Coindet, Cécile,Comel, Alain,Kirsch, Gilbert
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p. 6101 - 6104
(2007/10/03)
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