- Modular 2,3-diaryl-2: H -azirine synthesis from ketoxime acetates via Cs2CO3-mediated cyclization
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A modular 2H-azirine synthesis from ketoxime acetates via Cs2CO3-mediated cyclization has been developed. The reaction utilizes easily available starting materials and provides a general synthetic route to 2,3-diaryl-2H-azirines in good to excellent yields under mild conditions, which is complementary to the conventional approaches for the synthesis of 2H-azirines. A gram-scale reaction was performed to demonstrate the scale-up applicability of this synthetic method. Importantly, 2H-azirines can be efficiently converted to various azaheterocycles.
- Zhao, Mi-Na,Zhang, Wei,Wang, Xu-Cai,Zhang, Ying,Yang, De-Suo,Guan, Zheng-Hui
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supporting information
p. 4333 - 4337
(2018/06/21)
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- Palladium-catalyzed amination of aromatic C-H bonds with oxime esters
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"Chemical equation presented" We report a conceptually new approach to the direct amination of aromatic C-H bonds. In this process, an oxime ester function reacts with an aromatic C-H bond under redox-neutral conditions to form, in the case studied, an indole product. These reactions occur with relatively low catalyst loading (1 mol %) by a mechanism that appears to involve an unusual initial oxidative addition of an N-O bond to a Pd(0) species. The Pd(II) complex from oxidative addition of the N-X bond has been isolated for the first time, and evidence for the intermediacy of such oxidative addition products in the catalytic reaction has been gained.
- Tan, Yichen,Hartwig, John F.
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supporting information; experimental part
p. 3676 - 3677
(2010/05/15)
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- The Neber route to substituted indoles
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Two complementary procedures have been developed for the conversion of the oximes of α-aryl ketones to azirines. On heating, the azirines rearrange smoothly to the corresponding indoles. The overall transformation offers a versatile route to indoles, complementary to the Fischer indole synthesis. Copyright
- Taber, Douglass F.,Tian, Weiwei
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p. 1058 - 1059
(2007/10/03)
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- Titanium(III) Chloride Mediated Reduction of 1-Nitro-2-phenylethenes
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The reaction of 1-nitro-2-phenylethenes (β-nitrostyrenes) with aqueous titanium(III) chloride afforded substituted pyrroles in addition to the expected reduction products, oximes and carbonyl compounds. 2-Substituted 1-nitro-2-phenylethenes yielded divinylamine derivatives instead of pyrroles.The reaction mechanism has been rationalized by taking account of the electron transfer from titanium(III) species to the nitro olefines, followed by protonation, dimerization, cyclization, and/or hydrolysis.
- Sera, Akira,Fukumoto, Shoji,Tamura, Masako,Takabatake, Kiyoshi,Yamada, Hiroaki,Itoh, Kuniaki
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p. 1787 - 1791
(2007/10/02)
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- TITANIUM TRICHLORIDE MEDIATED REDUCTION OF NITROSTYRENES
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Reactions of substituted nitrostyrenes with aqueous titanium trichloride afforded pyrroles, carbonyl compounds, and oximes.In some instances, divinylamines were produced as well.The reaction mechanism is rationalized taking account of electron transfer to nitroethylenes from Ti(III), followed by protonation, dimerization, cyclization, and hydrolysis.
- Sera, Akira,Fukumoto, Shoji,Yoneda, Takako,Yamada, Hiroaki
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p. 697 - 702
(2007/10/02)
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- Wanderungstendenzen cyclischer, polycyclischer und methylverzweigter Alkylreste bei der Beckmann-Umlagerung
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The migration aptitudes of polycyclic bridgehead groups, cycloalkyl groups as well as of β-, γ- and δ-branched alkyl groups in the Chapman variant of the Beckmann rearrangement were determined.From these data it is concluded that at transition state 2 the migrating group is not resembling a planarised carbenium ion R+, but rather a pentacoordinated carbonium ion structure.Because only small geometrical changes occur in the migrating group vertical stabilisation of charge at transition state is believed to have significant influence on the migration aptitudes.
- Langhals, Heinz,Ruechardt, Christoph
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p. 3831 - 3854
(2007/10/02)
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