Doyle-Kirmse Reaction Using 3,3-Difluoroallyl Sulfide and N-Sulfonyl-1,2,3-triazole: An Efficient Access to gem-Difluoroallylated Multifunctional Quaternary Carbon

2021 ◽  
Author(s):  
Jiazhuang Wang ◽  
Jingwen Yu ◽  
Junyu Chen ◽  
Yubo Jiang ◽  
Tiebo Xiao
Keyword(s):  
Sigmatropic Rearrangement ◽  
Quaternary Carbon ◽  
Quaternary Center ◽  
Efficient Access

Doyle-Kirmse reaction of N-sulfonyl-1,2,3-triazole with 3,3-difluoroallyl sulfide through Rh(II)-catalyzed [2,3]-sigmatropic rearrangement has been developed, which affords an efficient access to multifunctional quaternary center containing aryl, imino, thio, and brominated gem-difluoroallyl....

scholarly journals Desymmetrization of cyclic 1,3-diketones via Ir-catalyzed hydrogenation: an efficient approach to cyclic hydroxy ketones with a chiral quaternary carbon

2019 ◽  
Vol 10 (25) ◽  
pp. 6350-6353 ◽  
Author(s):  
Quan Gong ◽  
Jialin Wen ◽  
Xumu Zhang
Keyword(s):  
Efficient Method ◽  
Quaternary Carbon ◽  
Efficient Approach ◽  
Quaternary Center ◽  
Hydroxy Ketones

We herein report an efficient method to synthesize cyclic hydroxy ketones with a chiral quaternary center.

Efficient preparation of chiral non-racemic sulfur compounds

2007 ◽  
Vol 85 (9) ◽  
pp. 603-618 ◽  
Author(s):  
Joannie Minville ◽  
Mélina Girardin ◽  
Claude Spino
Keyword(s):  
Sulfur Compounds ◽  
Sigmatropic Rearrangement ◽  
Chiral Auxiliary ◽  
Quaternary Carbon ◽  
Ring Closing Metathesis ◽  
Sulfur Containing

p-Menthane-3-carboxaldehyde serves as an efficient chiral auxiliary in the preparation of chiral non-racemic S-alkylthiocarbamates or S-dithiocarbonates via the 3,3-sigmatropic rearrangement of the corresponding alkylthionocarbamates or xanthates. The transfer of chirality during rearrangement is complete, and the final products possess a chiral tertiary or quaternary carbon bearing sulfur. The rearranged products are then transformed into enantiopure cyclic or acyclic sulfur-containing products, depending on the means of clivage of the auxiliary. The synthesis of a potent MMP-13 inhibitor is presented.Key words: 3,3-sigmatropic rearrangement, p-menthane-3-carboxaldehyde, S-alkylthiocarbamate, S-dithiocarbonate, alkylthionocarbamate, xanthate, ring-closing metathesis.

Bi(OTf)3-catalyzed C–H bond functionalization of azaarenes for the facile access to oxindoles featuring quaternary carbon centers

RSC Advances ◽  
2015 ◽  
Vol 5 (11) ◽  
pp. 8285-8288 ◽  
Author(s):  
Beili Lu ◽  
Qilin Lu ◽  
Senyang Zhuang ◽  
Jiajia Cheng ◽  
Biao Huang
Keyword(s):  
Quaternary Carbon ◽  
Bond Functionalization ◽  
Carbon Centers ◽  
Quaternary Center

Bi(OTf)3-catalyzed sp3 C–H functionalization of 2-alkyl azaarenes to isatylidene malononitriles has been achieved to give oxindoles containing an all-carbon quaternary center.

Bleaching ability of pre-hydrolyzed pulps in the context of a biorefinery mill

TAPPI Journal ◽  
2013 ◽  
Vol 12 (11) ◽  
pp. 49-53 ◽  
Author(s):  
CHRISTINE CHIRAT ◽  
LUCIE BOIRON ◽  
DOMINIQUE LACHENAL
Keyword(s):  
Carbon Content ◽  
Acid Hydrolysis ◽  
13C Nmr ◽  
Kraft Lignin ◽  
Kappa Number ◽  
Hydroxyl Groups ◽  
Kraft Pulps ◽  
Quaternary Carbon ◽  
Oxygen Delignification

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.

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