133871-04-2Relevant academic research and scientific papers
Benzyne-Mediated Esterification Reaction
Li, Yang,Shi, Jiarong,Zhao, Jinlong
supporting information, p. 7274 - 7278 (2021/10/01)
A benzyne-mediated esterification of carboxylic acids and alcohols under mild conditions has been realized, which is made possible via a selective nucleophilic addition of carboxylic acid to benzyne in the presence of alcohol. After a subsequent transesterification with alcohol, the corresponding esters can be produced efficiently. This benzyne-mediated protocol can be used on the modification of Ibuprofen, cholesterol, estradiol, and synthesis of nandrolone phenylpropionate. In addition, benzyne can also be used to promote lactonization and amidation reaction.
Aerobic Acyloxylation of Allylic C?H Bonds Initiated by a Pd0 Precatalyst with 4,5-Diazafluoren-9-one as an Ancillary Ligand
Kozack, Caitlin V.,Sowin, Jennifer A.,Jaworski, Jonathan N.,Iosub, Andrei V.,Stahl, Shannon S.
, p. 3003 - 3007 (2019/06/17)
Palladium-catalyzed allylic C?H oxidation has been widely studied, but most precedents use acetic acid as the coupling partner. In this study, a method compatible with diverse carboxylic acid partners has been developed. Use of a Pd0 precatalyst under aerobic reaction conditions leads to oxidation of Pd0 by O2 in the presence of the desired carboxylic acid to generate a PdII dicarboxylate that promotes acyloxylation of the allylic C?H bond. Good-to-excellent yields are obtained with a roughly 1:1 ratio of the alkene and carboxylic acid reagents. Optimized reaction conditions employ 4,5-diazafluoren-9-one (DAF) as a ligand, in combination with a quinone/iron phthalocyanine cocatalyst system to support aerobic catalytic turnover.
Metal-free carbon-carbon cross-couplings between the ion pairs in sulfonium tetraphenylborates
Xu, Mei-Li,Huang, Wenhua
, p. 4230 - 4232 (2014/07/22)
A series of sulfonium tetraphenylborates can be readily prepared by the metathesis of sulfonium halides with sodium tetraphenylborates. After heating at 120-150 °C, the sulfonium tetraphenylborates can smoothly undergo the cross-couplings between the tetraphenylborate anions and the sulfonium cations in the absence of a metal catalyst. For carbonylmethyl-, benzyl-, and allylsulfoniums, the corresponding carbonylmethyl-phenyl, benzyl-phenyl, and allyl-phenyl cross-coupling products can be obtained in 22-76% yields. An interionic electron-transfer mechanism for this cross-coupling reaction is proposed.
Pd-catalyzed carbonylation of diazo compounds at atmospheric pressure: A catalytic approach to ketenes
Zhang, Zhenhua,Liu, Yiyang,Ling, Lin,Li, Yuxue,Dong, Yian,Gong, Mingxing,Zhao, Xiaokun,Zhang, Yan,Wang, Jianbo
supporting information; experimental part, p. 4330 - 4341 (2011/06/21)
The carbonylation of carbenes through catalytic cycles is highly desirable due to the importance of ketene-mediated reactions in organic synthesis. In this investigation, a highly efficient and mild catalytic approach toward ketene intermediates has been developed based on Pd-catalyzed carbonylation of diazo compounds with CO. When α-diazocarbonyl compounds or N-tosylhydrazone salts are heated in the presence of a palladium catalyst under atmospheric pressure of CO, ketene intermediates are formed in situ, where they undergo further reactions with various nucleophiles such as alcohols, amines, or imines. The Pd-catalyzed tandem carbonylation-Staudinger cycloaddition gives β-lactam derivatives in good yields with excellent trans diastereoselectivity. The results from DFT calculation on the reaction mechanism suggest that Pd is involved in the [2 + 2] cycloaddition process and affects the diastereoselectivity of the β-lactam products by assisting isomerization of the addition intermediate. On the other hand, the acylketenes generated from the Pd-catalyzed carbonylation of α-diazoketones react with imines in a formal [4 + 2] cycloaddition manner to afford 1,3-dioxin-4-one derivatives. This straightforward carbonylation provides a new approach toward highly efficient catalytic generation of ketene species under mild conditions.
Studies on the structure-activity relationship of bicifadine analogs as monoamine transporter inhibitors
Zhang, Mingzhu,Jovic, Florence,Vickers, Troy,Dyck, Brian,Tamiya, Junko,Grey, Jonathan,Tran, Joe A.,Fleck, Beth A.,Pick, Rebecca,Foster, Alan C.,Chen, Chen
scheme or table, p. 3682 - 3686 (2009/04/06)
Compounds with various activities and selectivities were discovered through structure-activity relationship studies of bicifadine analogs as monoamine transporter inhibitors. The norepinephrine-selective 2-thienyl compound S-6j was efficacious in a rodent
A simple procedure for the esterification of alcohols with sodium carboxylate salts using 1-tosylimidazole (TsIm)
Soltani Rad, Mohammad Navid,Behrouz, Somayeh,Faghihi, Mohammad Ali,Khalafi-Nezhad, Ali
, p. 1115 - 1120 (2008/09/17)
An efficient and selective method for esterification of alcohols using N-(p-toluenesulfonyl)imidazole (TsIm) is described. In this method, alcohols are refluxed with a mixture of RCO2Na (R: alkyl and aryl), TsIm, and triethylamine in the presence of catalytic amounts of tetra-n-butylammonium iodide (TBAI) in DMF to afford the corresponding esters in good yields. This methodology is highly efficient for various structurally diverse alcohols with selectivity for ROH: 1° > 2° > 3°.
Zwitterionic salts as mild organocatalysts for transesterification
Ishihara, Kazuaki,Niwa, Masatoshi,Kosugi, Yuji
supporting information; experimental part, p. 2187 - 2190 (2009/05/27)
(Chemical Equation Presented) The exothermic reaction of 3,5-bis(trifluoromethyl)phenyl or 4-nitrophenyl isothiocyanate with 4-pyrrolidinopyridine (PPY) gave the corresponding arylaminothiocarbonylpyridinium salts in quantitative yields. These novel zwitterionic salts were effective as organocatalysts for the transesterification reaction of an equimolar mixture of methyl carboxylates and alcohols in hydrocarbons such as heptane and octane under azeotropic reflux conditions with the removal of methanol. In sharp contrast, PPY was inert as a catalyst under the same reaction conditions.
Mild and efficient aryl-alkenyl coupling via Pd(II) catalysis in the presence of oxygen or Cu(II) oxidants
Parrish, Jay P.,Jung, Young Chun,Shin, Seung Il,Jung, Kyung Woon
, p. 7127 - 7130 (2007/10/03)
We report herein a mild and efficient method for carbon-carbon bond formation between aryl stannanes and olefins via Pd(II) catalysis in the presence of oxygen or Cu(II) oxidants as a reoxidant. The process allows reactions between various olefins and aryl stannanes of varying electron density. Coupling methods under these oxidation conditions are comparatively described, and the benefits and limitations are also discussed.
Generation of esters from carboxylic acids using Appel's salt (4,5-dichloro-1,2,3-dithiazolium chloride)
Folmer,Weinreb
, p. 2737 - 2740 (2007/10/02)
Esters can be generated directly in good yields under mild conditions from the corresponding carboxylic acid and alcohol using Appel's salt (4,5-dichloro-1,2,3-dithiazolium chloride) and 2,6-lutidine.
