- Water-promoted dehydrative coupling of 2-aminopyridines in heptane: Via a borrowing hydrogen strategy
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A synthetic method for dehydrative N-benzylation promoted by water molecules in heptane using a π-benzylpalladium system has been developed. The presence of water significantly accelerates carbon-nitrogen bond formation, which is accomplished in an atom-economical process to afford the corresponding N-monobenzylated products. A crossover experiment afforded H/D scrambled products, which is consistent with a borrowing hydrogen mechanism. Kinetic isotope effect measurements revealed that benzylic carbon-hydrogen bond cleavage was the rate-determining step.
- Azumaya, Isao,Hikawa, Hidemasa,Kikkawa, Shoko,Nakayama, Taku
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p. 23144 - 23150
(2021/07/21)
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- Copper-catalyzed direct amination of benzylic hydrocarbons and inactive aliphatic alkanes with arylamines
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A new synthetic method toward direct C-N bond formation through saturated C-H amination of benzylic hydrocarbons and inactive aliphatic alkanes with primary aromatic amines under an inexpensive catalyst/oxidant (Cu/DTBP) system has been developed. Both aminopyridines and anilines could react smoothly with primary and secondary benzylic C-H substrates or cyclohexane to form the corresponding aromatic secondary amines in moderate to good yields. This protocol has the advantages of wide functional group tolerance and use of readily available raw materials.
- Jin, Shengzhou,Lin, Sen,Xie, Bo,Yan, Zhaohua,Yao, Hua,Zhong, Xiaoyang
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supporting information
p. 3263 - 3268
(2020/05/14)
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- Base-mediated cascade amidination/: N -alkylation of amines by alcohols
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A base-mediated cascade amidination/N-alkylation reaction of amines by alcohols has been developed. For the first time, nitriles have been identified as an efficient and benign water acceptor reagent in N-alkylation. Notably, the procedure tolerates a series of functional groups, such as methoxyl, halo, vinyl and hetero groups, providing a convenient method to construct different substituted diamino compounds, 15N labeled amine and could be scaled up to 1 mol scale offering 138.7 g of the desired product in good yield in one-pot. Mechanistic studies provided strong evidence for the amidination of amines with nitriles facilitated by t-BuOK.
- Hu, Mao-Lin,Jia, Xiaofei,Liang, Zuyu,Lu, Fenghong,Zhang, Chunyan,Zhang, Guoying
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supporting information
p. 10489 - 10492
(2020/10/02)
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- A borrowing hydrogen methodology: Palladium-catalyzed dehydrative: N -benzylation of 2-aminopyridines in water
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We demonstrate a greener borrowing hydrogen methodology using the π-benzylpalladium system, which offers an efficient and environmentally friendly dehydrative N-monobenzylation of 2-aminopyridines with benzylic alcohols in the absence of base. The crossover experiment using benzyl-α,α-d2 alcohol and 3-methylbenzyl alcohol afforded H/D scrambled products, suggesting that the dehydrative N-benzylation in our catalytic system involves a borrowing hydrogen pathway. KIE experiments show that C-H bond cleavage at the benzylic position of benzyl alcohol is involved in the rate-determining step (KIE = 2.9). This simple base-free protocol can be achieved under mild conditions in an atom-economic process, affording the desired products in moderate to excellent yields.
- Hikawa, Hidemasa,Imamura, Hirokazu,Kikkawa, Shoko,Azumaya, Isao
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supporting information
p. 3044 - 3049
(2018/07/13)
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- A metal-free tandem demethylenation/C(sp2)-H cycloamination process of N -Benzyl-2-aminopyridines via C-C and C-N bond cleavage
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A mild, metal-free synthesis of pyrido[1,2-a]benzimidazoles starting with N-benzyl-2-aminopyridines, which employs PhI(OPiv)2 as a stoichiometric oxidant, has been developed. The process is initiated by an unusual PhI(OPiv)2-mediated ipso SEAr reaction, followed by solvent-assisted C-C and C-N bond cleavage.
- Liang, Dongdong,He, Yimiao,Liu, Lanying,Zhu, Qiang
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supporting information
p. 3476 - 3479
(2013/07/26)
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- Electrophilic Benzylation of 2-Aminopyridine Ring
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In the reaction of 2-aminopyridine and its 3- or 5-methyl derivatives with benzyl chloride used in a molar ratio of 1:2, benzylation of 2-aminopyridine ring has been stated that 2-amino-3- or 5-benzylpyridines c as the major products were obtained.Formation of c type compounds took place in the decomposition of 2-benzylamino-3- or 5-benzylpyridines b obtained in the reaction of the 2-benzylaminopyridines a, excess benzyl chloride was used.Production of the b and c compounds, where the benzyl substituent occupied position 3 or 5 in 2-aminopyridine supported the electrophilic mechanism of the reaction (radical reaction was excluded).In the case of 2-aminopyridine and its 3-methyl derivative bis-(2-amino-5-pyridyl)phenylmethanes d were formed as the by-products.
- Kowalski, Piotr
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p. 875 - 879
(2007/10/02)
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