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排序方式: 共有113条查询结果,搜索用时 46 毫秒
21.
A Pd-catalyzed coupling-type reaction of aldehydes and organoboronic acids was achieved in the presence of P(1-nap)3, using Cs2CO3 in toluene, providing diaryl ketones with yields ranged from moderate to excellent. The efficiency of this reaction was demonstrated by the compatibility with nitro, cyano, trifluoromethyl, fluoro and chloro groups. Moreover, the rigorous exclusion of air/moisture is not required in these transformations. 相似文献
22.
María Torrado 《Tetrahedron letters》2007,48(2):323-326
A series of substituted tetralones as intermediates of CNS agents has been synthesized via Pd-catalyzed coupling reactions of 3-(methoxycarbonyl)-1,2,3,4-tetrahydro-1-oxonaphthalen-6-yl trifluoromethanesulfonate (5) with a variety of organometallic reagents. 相似文献
23.
Radhey M. Singh Atish Chandra Neha SharmaBhawana Singh Ritush Kumar 《Tetrahedron》2012,68(45):9206-9210
Bidentate phosphine ligands in palladium-catalyzed intramolecular Heck reactions of 2-chloroquinolin-3-yl-(1-homoallyl)alcohols are described to afford facile synthesis of 3-methylene-2,3-dihydro-1H-cyclopenta[b]quinolines in improved yields. We further observed using bulky aromatic phosphine ligand in Pd-catalyzed intermolecular Heck coupling reaction at olefinic centers with iodobenzene also favored exclusively Heck products in excellent yield. 相似文献
24.
Eric C. Hansen 《Tetrahedron letters》2004,45(38):7151-7155
A variety of 2-alkenyl-4-methylene tetrahydropyrans were synthesized via consecutive transition metal-catalyzed bond forming processes. In this approach, ruthenium-catalyzed coupling of homoallylic carbonates and homopropargylic alcohols generates substrates containing the requisite functionality for a palladium-mediated cyclization, thereby providing concise access to the target structures. The installation of a trisubstituted alkene at the C-2 position was achieved using an olefin cross metathesis process. 相似文献
25.
Boronic acids are important intermediates and molecular recognition moieties in a wide variety of applications. In our research, we have found that the synthesis of ortho-substituted arylboronic acids is problematic with the commonly used bis(pinacolato)diboron in palladium-mediated borylation reactions. As a substitute, we have found that bis(neopentyl glycolato)diboron is a much more efficient borylation agent for the synthesis of sterically hindered ortho-substituted arylboronic acids. 相似文献
26.
Shunji Ito Tomomi Terazono Tetsuo Okujima Toshihiro Murafuji Kunihide Fujimori Akio Tajiri 《Tetrahedron》2004,60(25):5357-5366
This paper describes an efficient preparation of 2-azulenylboronate (6) starting from 2-iodoazulene by halogen-metal exchange reaction using n-BuLi and subsequent quenching with 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane. The boronate 6 has been found to undergo Pd-catalyzed Miyaura-Suzuki cross-coupling reaction with a range of aryl bromides including aromatic poly bromides utilizing Pd2(dba)3-P(t-Bu)3 as a catalyst and establishes a strategy to produce novel poly(2-azulenyl)benzenes, some of which are found to be insoluble in common organic solvents, however. The redox behavior of 2-arylazulenes and poly(2-azulenyl)benzenes was examined by cyclic voltammetry (CV) and compared with those of 6-azulenylbenzene derivatives reported previously. 相似文献
27.
Reaction of symmetrical and unsymmetrical alkynes with arylboronic acids, using PdCl2 as catalyst source and i-Pr2NPPh2 as ligand, afforded trisubstituted alkenes with regioselectivity in good to excellent yields without a common additional acetic acid. Its efficiency has been demonstrated by its good functional groups, high yield and crowded substrates. 相似文献
28.
Sobha P. Gorugantula 《Tetrahedron》2010,66(10):1800-4757
Palladium-catalyzed, carbon monoxide-mediated reductive N-heterocyclization of nitro-heteroaromatic compounds having an alkene adjacent to the nitro-group affords bicyclic pyrrolo-fused heteroaromatic molecules. This type of reaction was used to prepare the fused bicyclo[3.3.0] ring-system: thieno[3,2-b]pyrrole, thieno[2,3-b]pyrrole, furo[2,3-b]pyrrole, pyrrolo[3,2-d]thiazole, and pyrrolo[2,3-d]imidazole and the bicyclo[4.3.0] ring-systems: pyrrolo[3,2-b]pyridine, pyrrolo[2,3-b]pyridine, pyrrolo[3,2-c]pyridine, pyrrolo[2,3-c]pyridine, pyrrolo[3,2-c]pyridazine, and pyrrolo[3,2-d]pyrimidine in 32-94% yield. 相似文献
29.
Ying Chen 《Tetrahedron letters》2005,46(30):4965-4969
A series of novel meso-chiral porphyrins were effectively synthesized from reactions of 5,15-dibromo-10,20-diarylporphyrins with readily available chiral alcohols and amides via palladium-mediated C-N and C-O bond formations. Cobalt complexes of these chiral porphyrins were prepared and shown to be effective catalysts for cyclopropanation of styrene with ethyl diazoacetate under mild and practical conditions, affording the desired cyclopropane ester as a trans-dominant form in excellent yields. Due to orientation and flexibility of the chiral appendages, only low enantioselectivity was observed. 相似文献
30.
Irina-Claudia Grig-Alexa Adriana-Luminita Finaru Lucia Ivan Paul Caubère 《Tetrahedron letters》2004,45(11):2343-2346
Various 4-substituted dihydrodipyridopyrazines were synthesized by palladium-mediated cross-coupling reactions. Starting from the corresponding 4-iodo or 4-bromo derivatives, the incorporation of aryl, vinyl, alkynyl and methoxycarbonyl groups is described. 相似文献