- Rhodium-catalyzed annulation of tertiary aniline N-oxides to N-alkylindoles: Regioselective C-H activation, oxygen-atom transfer, and N-dealkylative cyclization
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[Cp?RhIII]-catalyzed annulation of tertiary aniline N-oxides with alkynes was reported to achieve the challenging ortho C-H functionalization of tertiary anilines via N-O bond acting as a traceless directing group. More significantly, this system represents the first example which integrates C-H activation, oxygen-atom transfer, and N-dealkylative cyclization in one reaction. This unprecedented coupling reaction has allowed the construction of N-alkylindole derivatives in high efficiency with broad substrate scope and good functional group tolerance.
- Li, Bin,Xu, Hong,Wang, Huanan,Wang, Baiquan
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p. 3856 - 3862
(2016/07/06)
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- A Versatile, Traceless C-H Activation-Based Approach for the Synthesis of Heterocycles
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A versatile, traceless C-H activation-based approach for the synthesis of diversified heterocycles is reported. Rh(III)-catalyzed, N-amino-directed C-H alkenylation generates either olefination products or indoles (in situ annulation) in an atom- and step-economic manner at room temperature. The remarkable reactivity endowed by this directing group enables scale-up of the reaction to a 10 g scale at a very low catalyst loading (0.01 mol %/0.1 mol %). Ex situ annulation of olefination product provides entry into an array of heterocycles.
- Zhou, Shuguang,Wang, Jinhu,Zhang, Feifei,Song, Chao,Zhu, Jin
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supporting information
p. 2427 - 2430
(2016/06/09)
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- Co(III)-Catalyzed, Internal and Terminal Alkyne-Compatible Synthesis of Indoles
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A Co(III)-catalyzed, internal and terminal alkyne-compatible indole synthesis protocol is reported herein. The N-amino (hydrazine) group imparts distinct, diverse reactivity patterns for directed C-H functionalization/cyclization reactions. Notable synthetic features include regioselectivity for a meta-substituted arylhydrazine, regioselectivity for a chain-branched terminal alkyne, formal incorporation of an acetylenic unit through C2-desilylation on a C2-silylated indole derivative, formal inversion of regioselectivity through consecutive C3-derivatization and C2-desilylation processes, and formal bond migration for a linear-chain terminal alkyne.
- Zhou, Shuguang,Wang, Jinhu,Wang, Lili,Chen, Kehao,Song, Chao,Zhu, Jin
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supporting information
p. 3806 - 3809
(2016/08/16)
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- Ruthenium(II)-Catalyzed Traceless C?H Functionalization Using an N?N Bond as an Internal Oxidant
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A previously elusive RuII-catalyzed N?N bond-based traceless C?H functionalization strategy is reported. An N-amino (i.e., hydrazine) group is used for the directed C?H functionalization with either an alkyne or an alkene, affording an indole derivative or olefination product. The synthesis features a broad substrate scope, superior atom and step economy, as well as mild reaction conditions.
- Zhou, Shuguang,Wang, Jinhu,Chen, Pei,Chen, Kehao,Zhu, Jin
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supporting information
p. 14508 - 14512
(2016/10/03)
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- Novel synthesis of 2-aryl and 2,3-disubstituted indoles by modified double elimination protocol
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(Chemical Equation Presented) Syntheses of 2-aryl and 2,3-substituted indoles were realized by modified double elimination protocol. Under basic conditions, vinyl sulfones derived from the reaction of 2-aminobenzyl sulfone with benzaldehydes underwent cyclization and alkylation followed by elimination of sulfinic acid to afford 2,3-substituted indoles.
- Babu, Govindarajulu,Orita, Akihiro,Otera, Junzo
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p. 4641 - 4643
(2007/10/03)
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- DIBORANE AS A REDUCING AGENT - VI. THE NOVEL REDUCTION OF INDOLE-1-CARBOXALDEHYDES TO 1-METHYL-INDOLES, DI(INDOLYLMETHYL)ETHERS AND INDOLYLMETHYL INDOLINES
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Reduction of the indole-1-carboxaldehydes (1a-1f) with borane/THF gives the 1-methylindoles (4) in 42-91 percent yields together with the di(indolylmethyl)ethers (8), the indolylmethyl indolines (7), the unsymmetric ether (10) and the indolenine (11) as the minor products, except 7a.This appears to be the first report on the formation of symmetric ethers in the borane/THF reduction of an oxygen function.The formation of 7a and 7b from 1a and 1b implies that electrophilic substitution takes place primarily at position 3 of 3-substituted indoles. 1c-1f did not form the corresponding 7 probably because of steric hindrance.These results are discussed in relation to the mechanisms of borane/THF reduction, origin of the different products and electrophilic substitution in 3-substituted indoles.
- Biswas, M. Kshetra,Dhara, Rabindranath,Roy, Sumita,Mallik, Haimanti
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p. 4351 - 4357
(2007/10/02)
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