ChemInform Abstract: Rh(III)-Catalyzed C-H Activation Reactions Forming 1H-Isoindoles Containing a Quaternary Carbon Center from Aryl Ketones or Benzylamines.

ChemInform ◽  
2016 ◽  
Vol 47 (51) ◽  
Author(s):  
Yeonhui Yi ◽  
Hyejeong Lee ◽  
Chul-Ho Jun
2016 ◽  
Vol 52 (66) ◽  
pp. 10171-10174 ◽  
Author(s):  
Yeonhui Yi ◽  
Hyejeong Lee ◽  
Chul-Ho Jun

Rh(iii)/Cu(OAc)2 catalyzed, one-pot reactions of aryl ketones, acrylate esters and ammonium acetate or α-substituted benzylamines under microwave irradiation conditions produce 1H-isoindoles bearing a quarternary carbon center.


TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 49-53 ◽  
Author(s):  
CHRISTINE CHIRAT ◽  
LUCIE BOIRON ◽  
DOMINIQUE LACHENAL

Autohydrolysis and acid hydrolysis treatments were applied on mixed softwood chips. The cooking ability was studied by varying the alkali and duration of the cook. Pulps with kappa numbers varying from 30 to 70 were obtained. The bleaching ability of these pulps was studied and compared to control kraft pulps. The prehydrolyzed pulps were shown to be more efficiently delignified by oxygen than the control kraft pulps starting from the same kappa number. Furthermore, the final bleaching was also easier for these pulps. It was also shown that extensive oxygen delignification applied on high-kappa pre-hydrolyzed pulps could be a way to improve the overall yield, which is a prerequisite for the development of such biorefinery concepts. Lignin was isolated from the control kraft and the two pre-hydrolyzed kraft pulps and analyzed by 13C NMR. Lignins from pre-hydrolyzed kraft pulps had similar free phenolic groups content to the control kraft lignin, but their aliphatic hydroxyl groups and β-O-4 content were lower than for the control lignin. The quaternary carbon content was the same for all the samples.


2018 ◽  
Author(s):  
Tanner C. Jankins ◽  
Robert R. Fayzullin ◽  
Eugene Khaskin

We report a one-step, Ru(II)-catalyzed cyclopropanation reaction that is conceptually different from the previously reported protocols that include Corey-Chaykovsky, Simmons-Smith, and metal catalyzed carbene attack on olefins. Under the current protocol, various alcohols are transformed into sulfone substituted cyclopropanes with excellent isolated yields and diastereoselectivities. This new reaction forms highly congested cyclopropane products with three new C–C bonds, three or two new chiral centers and one new quaternary carbon center. 22 examples of isolated substrates are given. Previously reported synthetic routes for similar substrates are all multi-step, linear routes that proceed with overall low yields and poor control of stereochemistry. Experimental mechanistic investigations suggest initial metal-catalyzed dehydrogenation of the alcohol substrate and catalyst independent stepwise attack of two equivalents of sulfone on the aldehyde under basic conditions. While the Ru(II) is only responsible for the initial dehydrogenation step, the rate of aldehyde formation is crucial to maintaining the right balance of intermediates needed to afford the cyclopropane product.


2019 ◽  
Vol 84 (21) ◽  
pp. 13871-13880 ◽  
Author(s):  
Xie-Chao Yang ◽  
Jin-Yu Liu ◽  
Zhen Liu ◽  
Xiu-Qin Hu ◽  
Peng-Fei Xu

2019 ◽  
Vol 21 (2) ◽  
pp. 503-507 ◽  
Author(s):  
Pei Zhang ◽  
Qiuhong Huang ◽  
Yuyu Cheng ◽  
Rongshi Li ◽  
Pengfei Li ◽  
...  

Author(s):  
Pan Xie ◽  
Cheng Xue ◽  
Cancan Wang ◽  
Dongdong Du ◽  
Sanshan Shi

A CF3SO2Na/Pd(OAc)2 co-catalyzed strategy is developed to produce aryl ketones via visible-light-induced decarboxylative cross-coupling of α-oxocarboxylic acids and aryl boronic acids. This process was perfomed under air at room temperature,...


Author(s):  
Jiajia Zhang ◽  
De Chen ◽  
yiqun qin ◽  
Wei Deng ◽  
Yongyue luo ◽  
...  

A metal-free oxidative alkene alkylation/alkynylation of 1,4-enyn-3-ols with alkylaldehydes has been achieved, which offers a general access to the challenging quaternary carbon-containing but-3-yn-1-ones. The method features with excellent functional group...


RSC Advances ◽  
2021 ◽  
Vol 11 (14) ◽  
pp. 8051-8054
Author(s):  
Rongxiang Chen ◽  
Bing Liu ◽  
Wenbo Li ◽  
Kai-Kai Wang ◽  
Changqing Miao ◽  
...  

A cross dehydrogenative coupling reaction of aryl ketones with N-hydroxyphthalimide was realized. The reactions afforded a clean and facile access to diverse N-alkoxyphthalimide derivatives in high yields (up to 99%).


Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 671
Author(s):  
Chad M. Bernier ◽  
Joseph S. Merola

A series of chiral complexes of the form Ir(NHC)2(aa)(H)(X) (NHC = N-heterocyclic carbene, aa = chelated amino acid, X = halide) was synthesized by oxidative addition of -amino acids to iridium(I) bis-NHC compounds and screened for asymmetric transfer hydrogenation of ketones. Following optimization of the reaction conditions, NHC, and amino acid ligands, high enantioselectivity was achieved when employing the Ir(IMe)2(l-Pro)(H)(I) catalyst (IMe = 1,3-dimethylimidazol-2-ylidene), which asymmetrically reduces a range of acetophenone derivatives in up to 95% enantiomeric excess.


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