共查询到20条相似文献,搜索用时 15 毫秒
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Wasa M Engle KM Lin DW Yoo EJ Yu JQ 《Journal of the American Chemical Society》2011,133(49):19598-19601
Systematic ligand development has led to the identification of novel mono-N-protected amino acid ligands for Pd(II)-catalyzed enantioselective C-H activation of cyclopropanes. A diverse range of organoboron reagents can be used as coupling partners, and the reaction proceeds under mild conditions. These results provide a new retrosynthetic disconnection for the construction of enantioenriched cis-substituted cyclopropanecarboxylic acids. 相似文献
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Bruce H. Lipshutz Daniel Pollart Joseph Monforte Hiyoshizo Kotsuki 《Tetrahedron letters》1985,26(6):705-708
PdCl2(CH3CN)2 catalyzes the hydrolysis of dioxolane acetals and ketals in moist CH3CN, while in acetoze, efficient and more reproducible exchange reactions take place. 相似文献
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Pd-catalyzed highly para-selective C-H arylation of monosubstituted arenes (including toluene) is developed for the first time using an F(+) reagent as a bystanding oxidant. This finding provides a new retrosynthetic disconnection for para-substituted biaryl synthesis via C-H/C-H cross-coupling. 相似文献
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Xiang-Ying Tang 《Tetrahedron》2009,65(43):8863-778
Pd(0) catalyzed reactions of methylenecyclopropyl carbonyl compounds afforded a convenient method for the synthesis of conjugate (E,E)-1,3-diene derivatives 2 in good to excellent yields. Moreover, we also found that Pd(II)-catalyzed reactions of methylenecyclopropyl carbonyl compounds with water gave 1,5-diketones in good to high yields via a carbene-palladium intermediate. The plausible reaction mechanisms have also been provided on the basis of control and 18O-labeling experiments. 相似文献
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Pd(II)-catalyzed intramolecular amination of sp2 and sp3 C-H bonds are developed using a combination of CuCl2 and AgOAc as the oxidant. The reaction protocol tolerates the presence of a double bond in the substrates. This catalytic reaction provides practical access to a wide range of beta-, gamma-, and delta-lactams. 相似文献
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Need some direction? Silanol was developed as a directing group for the Pd(II)-catalyzed oxidative Heck-type reaction of arenes. A one-pot C-H activation/desilylation process of benzyldiisopropylsilanol was also demonstrated, providing a powerful approach for the synthesis of ortho-alkenyl-substituted alkylarenes. Considering the easily attachable and readily removable properties of the silanol group, this reaction will find broad synthetic applications. 相似文献
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Lin S Song CX Cai GX Wang WH Shi ZJ 《Journal of the American Chemical Society》2008,130(39):12901-12903
The first catalytic direct alkylation of allylic C-H bonds via Pd(II)-catalysis is described in the absence of base. Polysubstituted cyclic compounds can also be constructed by the intramolecular direct allylic alkylation. 相似文献
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A series of phosphines based on disaccharides containing a d-glucosamine framework were prepared and tested for their abilities as ligands for the palladium(0)-catalyzed asymmetric allylic allylation of racemic 1,3-diphenyl-2-propenyl acetate with various nucleophiles. In contrast to previous results exploiting monosaccharides, the iminophosphines generally afforded higher enantiomeric excesses, up to 99%. 相似文献
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A highly efficient and selective palladium-catalyzed diarylation of (2-azaaryl)methanes at the methyl group is described. Aryl chlorides proved reactive enough. A palladium η(3)-azaallyl intermediate has been identified on the basis of DFT studies. 相似文献
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This work demonstrates a general and efficient method to prepare conjugated dienes by Pd(II)-catalyzed direct olefination of unactivated alkenes with allylic esters and acrylates via vinylic C-H activation. Various aryl and heteroaryl alkenes as well as aliphatic alkenes all give the desired linear 1,3-butadienes with retention of the traditional leaving groups such as OAc and other carboxylic acid ester groups. 相似文献
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Jordan-Hore JA Johansson CC Beck EM Gaunt MJ 《Journal of the American Chemical Society》2008,130(48):16184-16186
We report a new Pd(II)-catalyzed C-H bond amination reaction to form carbazoles, an important motif that is prevalent in a range of systems. The catalytic amination process operates under extremely mild conditions and produces carbazole products in good to excellent yields. Carbazoles possessing complex molecular architecture can also be formed using this reaction, highlighting its potential in natural product synthesis applications. Preliminary mechanistic investigations reveal the reaction proceeds through a Pd(II)/Pd(IV) manifold and that reductive elimination from a high oxidation state Pd(IV) complex facilitates the mild conditions of this transformation. 相似文献
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Masayuki Wasa 《Tetrahedron》2010,66(26):4811-19601
Protocols to effect β-arylation of sp3 C-H bonds via Pd(II)/(IV) and Pd(0)/(II) catalytic cycles have been achieved using a newly developed monodentate CONHC6F5 directing group. These reactions provide an unprecedented means to functionalize sp3 C-H bonds in aliphatic carboxylic acid-derived substrates. 相似文献
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Elliott LD Wrigglesworth JW Cox B Lloyd-Jones GC Booker-Milburn KI 《Organic letters》2011,13(4):728-731
N-Ts and N-Boc derivatives of 1,2-diamines and 1,2-amino alcohols are shown to undergo efficient Pd(II)-catalyzed aza-Wacker reactions with a large range of electron-deficient alkenes. The resulting enamine intermediate generally undergoes cyclization with the second heteroatom to form 1,3-heterocycles. The sequence facilitates the rapid synthesis of saturated oxazolidines, imidazolidines, and their derivatives. Use of N-L-valinol derivatives results in highly diastereoselective reactions, where the net stereochemical outcome diverges between N-Ts and N-Boc. 相似文献
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Dong J Huang Y Qin X Cheng Y Hao J Wan D Li W Liu X You J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(20):6158-6162
Power of two: A widely functional-group tolerant, selective and rapid oxidative cross-coupling between two structurally similar azoles has been carried out by using a palladium/copper co-catalytic twofold C-H activation method (see scheme). 相似文献
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A new palladium(II) catalyzed methodology for the direct synthesis of alkylidene isoindolinones from N-alkoxybenzamides is presented. Isoindolinone formation proceeds through a highly efficient and E-selective C-H activation/Heck/Aza-Wacker sequence. Substoichiometric amounts of benzoquinone can be employed in a cooperative oxidation system with O(2), leading to facile purification of products. Modification of the reaction conditions provides a general route to substituted phthalimides by carbonylation with CO. Both systems were found to tolerate a wide range of functionality. 相似文献