1865-29-8Relevant articles and documents
Rhodium catalysed hydroformylation of unsaturated esters
Clarke, Matthew L.
, p. 4043 - 4045 (2004)
Rhodium catalysed hydroformylation of unsaturated esters has been studied. A pronounced temperature dependence was observed on the regioselectivity and catalytic activity for these reactions, and under the appropriate conditions, it is possible to obtain preferentially either linear or quaternary products. A quaternary selective hydroformylation of methyl atropate to give 1,3-aldehydic esters has also been developed.
Catalysis in supercritical CO2 using dendrimer-encapsulated palladium nanoparticles
Yeung,Lee C.T.,Johnston,Crooks
, p. 2290 - 2291 (2001)
Dendrimer-encapsulated nanoparticles are shown to be versatile catalysts for both the hydrogenation of styrene and Heck heterocoupling of iodobenzene and methacrylate in supercritical CO2 (scCO2).
Group 6 heteroatom- and non-heteroatom-stabilized carbene complexes. β,β′- and α,ββ′-Annulation reactions of cyclic enamines
Barluenga, Jose,Ballesteros, Alfredo,De la Rua, Ramon Bernardo,Santamaria, Javier,Rubio, Eduardo,Tomas, Miguel
, p. 1834 - 1842 (2003)
Cyclization reactions of group 6 Fischer carbene complexes with cyclopentanone and cyclohexanone enamines are described. Enamine 3a undergoes thermal β,β′-annulation with alkenylcarbene complexes 1 and 2 (THF, 60 °C), affording semibullvalenes 5. The metalate intermediates 6, resulting from β,β′-annulation of the enamines 3a and 4a, were quantitatively formed by running the reaction in hexane at room temperature. Acid-promoted demetalation of 6 afforded endo-2-bicyclo[3.2.1]octen-8-ones 7 and endo/exo-2-bicyclo[3.3.1]nonen-9-ones 8 (endo/exo = 5:1). Using (S)-methoxymethylpyrrolidinederived enamines 3b and 4b,c allowed highly enantioenriched cycloadducts endo-(+)-7 as well as endo- (-)-8 and exo-(-)-8 to be accessed. The non -heteroatom -stabilized carbene complex 10 was formed from complex 6 by Me3SiOTf-promoted elimination of the methoxy group, characterized by 13C NMR, and transformed into the organic compounds 7, 7-d, and 11 as well as into bicyclo[3.2.1]octan-2,8-diones 14 and cycloheptanones 15, On the basis of this sequence, enantioenriched cycloheptanones (+)-15 were efficiently prepared in one pot from carbene complexes 2 and enamine 3b (51-55% yield, 91-96% ee). Extension of this work to simple Fischer carbene complexes 16 allowed an appropriate way to generate the nonstabilized pentacarbonyl[(phenyl(alkyl)carbene]tungsten complex 17 to be designed, for which the thermal and chemical behavior leading to compounds 18-21 is described.
Room-temperature Pd-catalyzed methoxycarbonylation of terminal alkynes with high branched selectivity enabled by bisphosphine-picolinamide ligand
Chen, Fen-Er,Ke, Miaolin,Liu, Ding,Ning, Yingtang,Ru, Tong
supporting information, p. 1041 - 1044 (2022/01/28)
We report the room-temperature Pd-catalyzed methoxy-carbonylation with high branched selectivity using a new class of bisphosphine-picolinamide ligands. Systematic optimization of ligand structures and reaction conditions revealed the significance of both
Palladium-Catalyzed Asymmetric Hydroesterification of α-Aryl Acrylic Acids to Chiral Substituted Succinates
Ji, Xiaolei,Shen, Chaoren,Tian, Xinxin,Dong, Kaiwu
supporting information, p. 8645 - 8649 (2021/10/25)
A palladium-catalyzed asymmetric hydroesterification of α-aryl acrylic acids with CO and alcohol was developed, preparing a variety of chiral α-substituted succinates in moderate yields with high ee values. The kinetic profile of the reaction progress revealed that the alkene substrate first underwent the hydroesterification followed by esterification with alcohol. The origin of the enantioselectivity was elucidated by density functional theory computation.
Pyrrolidine integrin regulator and application thereof
-
, (2021/09/08)
Disclosed are a compound as represented by formula I, and a racemate, a stereoisomer, a tautomer, an isotopic marker, a nitrogen oxide, a solvate, a polymorph, a metabolite, an ester, and a prodrug thereof or a pharmaceutically acceptable salt thereof, and a pharmaceutical composition comprising same, a preparation method therefor, and the medical use thereof. The structure of formula I is as follows:
Electrochemical oxidative: Z -selective C(sp2)-H chlorination of acrylamides
Coles, Simon J.,Hareram, Mishra Deepak,Harnedy, James,Morrill, Louis C.,Tizzard, Graham J.
supporting information, p. 12643 - 12646 (2021/12/07)
An electrochemical method for the oxidative Z-selective C(sp2)-H chlorination of acrylamides has been developed. This catalyst and organic oxidant free method is applicable across various substituted tertiary acrylamides, and provides access to a broad range of synthetically useful Z-β-chloroacrylamides in good yields (22 examples, 73% average yield). The orthogonal derivatization of the products was demonstrated through chemoselective transformations and the electrochemical process was performed on gram scale in flow.
Iridium complex-linked porous organic polymers for recyclable, broad-scope photocatalysis of organic transformations
Xu, Zi-Yue,Luo, Yi,Zhang, Dan-Wei,Wang, Hui,Sun, Xing-Wen,Li, Zhan-Ting
supporting information, p. 136 - 143 (2020/01/21)
Two rigid porous organic polymers (Ir-POP-1 and Ir-POP-2) were prepared from the coupling reactions of tetraphenylmethane tetraborate and two [Ir(ppy)2(dtbbpy)]+-based bitopic linkers and applied as heterogeneous visible-light photocatalysts for organic transformations. Ir-POP-2 was found to exhibit high catalytic activity for a wide range of organic reactions, which include Smiles-Truce rearrangement of alkyliodides, desulfurative conjugate addition to Michael acceptors, and aerobic oxidations of sulfides and arylboronic acids. For all the transformations, Ir-POP-2 could achieve heterogeneous photocatalytic efficiency that rivals that of the homogeneous prototype iridium complexes. This remarkably high photocatalytic performance has been attributed to the large pore size of the conjugated backbone. The new heterogeneous photocatalyst was also highly stable to achieve good recyclability for all the studied reactions and could be reused eight to nineteen times.
Catalytic Hydroetherification of Unactivated Alkenes Enabled by Proton-Coupled Electron Transfer
Knowles, Robert R.,Metrano, Anthony J.,Tsuchiya, Yuto,Tsui, Elaine
supporting information, p. 11845 - 11849 (2020/05/22)
We report a catalytic, light-driven method for the intramolecular hydroetherification of unactivated alkenols to furnish cyclic ether products. These reactions occur under visible-light irradiation in the presence of an IrIII-based photoredox catalyst, a Br?nsted base catalyst, and a hydrogen-atom transfer (HAT) co-catalyst. Reactive alkoxy radicals are proposed as key intermediates, generated by direct homolytic activation of alcohol O?H bonds through a proton-coupled electron-transfer mechanism. This method exhibits a broad substrate scope and high functional-group tolerance, and it accommodates a diverse range of alkene substitution patterns. Results demonstrating the extension of this catalytic system to carboetherification reactions are also presented.
Palladium-catalyzed intermolecular C-H silylation initiated by aminopalladation
Ji, Xiaoming,Wei, Feng,Wan, Bin,Cheng, Cang,Zhang, Yanghui
supporting information, p. 7801 - 7804 (2020/07/27)
A Pd(ii)-catalyzed intermolecular C-H silylation reaction initiated by aminopalladation has been developed. The C-H bonds were activated by an alkyl Pd(ii) species generated through aminopalladation and then disilylated with hexamethyldisilane to form disilylated indolines as the final products. The reaction provides a new method for the introduction of silyl groups into complex organic molecules.
