- Dynamic Covalent Chemistry of Aldehyde Enamines: BiIII- and ScIII-Catalysis of Amine–Enamine Exchange
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The dynamic exchange of enamines from secondary amines and enolizable aldehydes has been demonstrated in organic solvents. The enamine exchange with amines was efficiently catalyzed by Bi(OTf)3 and Sc(OTf)3 (2 mol %) and the equilibria (60 mm) could be attained within hours at room temperature. The formed dynamic covalent systems displayed high stabilities in basic environment with 2 % by-product formation within one week after complete equilibration. This study expands the scope of dynamic C?N bonds from imine chemistry to enamines, enabling further dynamic methodologies in exploration of this important class of structures in systems chemistry.
- Zhang, Yang,Xie, Sheng,Yan, Mingdi,Ramstr?m, Olof
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p. 11908 - 11912
(2017/09/07)
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- Rhodium-catalyzed anti-markovnikov addition of secondary amines to arylacetylenes at room temperature
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An efficient method for synthesis of E-enamines by the anti-Markovnikov addition of secondary amines to terminal alkynes is described. The reaction of a variety of aryl- and heteroarylacetylenes proceeded at room temperature using a combination of a 8-quinolinolato rhodium complex and P(p-MeOC6H 4)3 as a catalyst. The products were obtained as enamines by simple bulb-to-bulb distillation.
- Sakai, Kazunori,Kochi, Takuya,Kakiuchi, Fumitoshi
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supporting information; experimental part
p. 3928 - 3931
(2011/10/01)
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- Isolation of catalytic intermediates in hydroamination reactions: Insertion of internal alkynes into a zirconium-amido bond
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Insert alkyne to continue: Reaction of a bis(ureate) zirconium dimethylamido complex with electron-rich alkynes leads to vinylamine insertion products (see scheme). The insertion of C=C unsaturated bonds into M=N bonds is proposed as a key step in lanthan
- Leitch, David C.,Turner, Courtney S.,Schafer, Laurel L.
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supporting information; experimental part
p. 6382 - 6386
(2010/12/19)
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- Broadening the scope of group 4 hydroamination catalysis using a tethered ureate ligand
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(Chemical Equation Presented) A broadly applicable group-4-based precatalyst for the hydroamination of primary and secondary amines was developed. Screening experiments involving a series of amide and urea proligands led to the discovery of a tethered bis(ureate) zirconium complex with unprecedented reactivity in the intermolecular hydroamination of alkynes and the intramolecular hydroamination of alkenes. This catalyst system is effective with primary and secondary amines, 1,2-disubstituted alkenes, and heteroatom-containing functional groups, including ethers, silanes, amines, and heteroaromatics. The gem-disubstituent effect is not required for cyclization. The catalyst is generally regioselective for the anti-Markovnikov product of intermolecular alkyne hydroamination, and chemoselective for hydroamination over C-alkylation when forming 6- and 7-membered rings from aminoalkenes.
- Leitch, David C.,Payne, Philippa R.,Dunbar, Christine R.,Schafer, Laurel L.
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supporting information; experimental part
p. 18246 - 18247
(2010/04/25)
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- Anti-Markovnikov addition of both primary and secondary amines to terminal alkynes catalyzed by the TpRh(C2H4)2/PPH 3 system
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Terminal alkynes react with secondary amines in the presence of TpRh(C2H4)2/PPh3 (Tp = trispyrazolylborate) to give anti-Markovnikov E-enamines. Both Tp and PPh3 ligands are essential for the reaction. The reaction tolerates functional groups, such as ester, nitrile, and siloxy groups, on the terminal alkynes. Primary amines also add to terminal alkynes in anti-Markovnikov fashion, yielding the corresponding imines. The formation of a vinylidene-rhodium complex followed by the intermolecular nucleophilic attack by an amine nitrogen at the α-carbon atom of the vinylidene-metal intermediate may be involved in a key step in the catalytic reaction. Copyright
- Fukumoto, Yoshiya,Asai, Harumi,Shimizu, Masaki,Chatani, Naoto
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p. 13792 - 13793
(2008/04/04)
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- A general synthesis of amines and hydrazines by oxidation of amidocuprates and zinc-amidocuprates
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A wide range of amines and hydrazines were synthesized according to an electrophilic amination protocol by oxidative decomposition of readily generated lithium- and zinc-amidocyanocuprates. Optimization of the yields was achieved by the appropriate combination of the organometallic cluster and the nature of the oxidizing agent.
- Cane,Brancaleoni,Dembech,Ricci,Seconi
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p. 545 - 548
(2007/10/03)
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- Reactions of 2,2,2-Trichloroethylamines with Grignard Reagents and Alkyllithiums
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2,2,2-Trichloro- and 2,2-dichloroethylamines were found to suffer monoalkylation with Grignard reagents and alkyllithiums giving, in the main, chain-lenghtened β,γ- or α,β-unsaturated amines.Which product is formed depends upon the individual structures o
- Takamatsu, Masanori,Terao, Yoshiyasu,Sekiya, Minoru
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p. 2682 - 2687
(2007/10/02)
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