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1.
We herein report that PtCl4 has proven to be a hydroarylation catalyst with an efficiency and substrate scope superior to previously known methods. This catalyst demonstrated consistent performance with arene-yne substrates of diverse structural features, including propargyl ethers, propargylamines, and alkynoate esters, providing good to excellent yields of the 6-endo products (chromenes, dihydroquinolines, and coumarins). In contrast, Pt(II), Pd(II), and Ga(III) salts were shown to be sensitive to the substitution on the alkyne moiety. PtCl4 is compatible with both terminal and disubstituted alkynes, as well as with various functionalities on the arene ring, including methyl, methoxyl, hydroxyl, protected amine, and halide. 相似文献
2.
Takaya Matsumoto 《Catalysis Surveys from Asia》2007,11(1-2):31-48
In this article, two kinds of our transition metal-catalyzed olefin arylations are summarized and discussed. The first one
is Ir-catalyzed novel anti-Markovnikov hydroarylation of olefins with benzene. Using this reaction catalyzed by [Ir(μ-acac-O,O′,C3)(acac-O,O′)(acac-C3)]2 (acac = acetylacetonato), 1, straight-chain alkylarenes, which were not obtainable by the conventional Friedel-Crafts aromatic alkylation with olefins,
were able to be successfully synthesized directly from arenes and olefins with the higher selectivity than that of branched
alkylarenes. This is the first efficient catalyst which shows the desirable high regioselectivity. The reaction of benzene
with propylene gave n-propylbenzene and cumene in 61% and 39% selectivities, respectively, and the reaction of benzene and styrene afforded 1,2-diphenylethane
in 98% selectivity. The reaction of alkylarene and olefin showed meta and para orientations. A wide range of olefins and arenes
can be employed for the synthesis of alkylarenes. The mechanism of the reaction involves C–H bond activation of benzene by
Ir center to form Ir–phenyl species. The second reaction is Rh-catalyzed oxidative arylation of ethylene with benzene to directly
produce styrene, namely one-step synthesis of styrene. The reaction of benzene with ethylene catalyzed by Rh(ppy)2(OAc) (ppyH = 2-phenylpyridine, OAc = acetate), 3 with Cu oxidizing agent gave styrene and vinyl acetate in 77% and 23% selectivities, respectively, in contrast to those by
Pd(OAc)2, 47% of styrene and 53% of vinyl acetate. The mechanism of the reaction involves Rh-mediated C–H bond activation of benzene,
which appears to be a rate-determining step. Furthermore, Rh complexes in a Rh(I) oxidation state at the beginning of the
reaction work as catalysts for the reaction by addition of acacH and O2 without any oxidizing agent, like Cu salt. 相似文献
3.
Omer Tahir Gunkara 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):909-916
AbstractThe regioselective synthesis of Polyhedral oligomeric silsesquioxane (POSS)-based norbornyl imide derivatives through palladium catalyzed Heck coupling reaction was reported on an effective synthetic method to organic–inorganic bio-hybrids serving as advanced materials. The reaction of POSS-based imide derivatives with various aryl iodides catalyzed by palladium acetate in the presence of triethyl amine, as the base, in DMF afforded the products in moderate yields. All new POSS derivatives were structurally characterized by FTIR, 1H, 13C NMR, HRMS and GC/MS analyses. 相似文献
4.
Justin S. Marcum Tiffany R. Taylor Prof. Simon J. Meek 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(33):14174-14179
A catalytic method for the site-selective and enantioselective synthesis of functionalized arenes by the intermolecular hydroarylation of terminal and internal 1,3-dienes with aryl pinacolato boronates is reported. The reactions are promoted by 5.0 mol % of a readily available monodentate phosphoramidite-Ni complex in ethanol, affording a variety of enantioenriched products in up to 96 % yield and 99:1 er. Mechanistic studies indicate that Ni–allyl formation is irreversible and related to the nature of the arylboronate. 相似文献
5.
Zhaohong Lu Stephen L. Buchwald 《Angewandte Chemie (International ed. in English)》2020,59(37):16128-16132
Arenes with β‐stereogenic centers are important substructures in pharmaceuticals and natural products. We have developed an asymmetric anti‐Markovnikov hydroarylation of 1,1‐disubstituted olefins by dual palladium and copper hydride catalysis as a convenient and general approach to access these substructures. This efficient one‐step process addresses several limitations of the traditional stepwise approaches. The use of cesium benzoate as a base and a common phosphine ligand for both the Cu‐ and Pd‐catalyzed processes were important discoveries that allow these challenging olefin substrates to be efficiently transformed. A variety of aryl bromide coupling partners, including numerous heterocycles, were coupled with 1,1‐disubstituted alkenes to generate arenes with β‐stereogenic centers. 相似文献
6.
《Green Chemistry Letters and Reviews》2013,6(4):621-632
Abstract Hydroarylation of styrene and its derivatives with arenes and heteroarenes was studied using Montmorillonite K-10 as an efficient, environmentally benign, economical, greener, and recyclable catalyst. The reaction gives 1,1-diarylalkanes with a very high selectivity and excellent yields in short time with greater substrate compatibility. 相似文献
7.
Hydroarylation of bicyclic alkenes has been developed using a low‐valent ReI‐catalyzed, directing group‐assisted C?H bond activation strategy. The addition of sodium acetate significantly improves the reaction efficiency; moreover, bicyclic alkenes such as 7‐oxa and aza benzonorbornadienes worked efficiently under this reaction condition. Preliminary mechanistic studies suggest that, after the alkene insertion, the rhenacycle preferentially undergoes protonolysis rather than reductive elimination. 相似文献
8.
We report a gold-catalyzed intramolecular hydroarylation of unactivated olefins using a combination of AuCl3/AgOTf as the catalytic system affording dihydrobenzopyrans, tetralins and tetrahydroquinolines in good yields. For our preliminary mechanistic studies, we have investigated the kinetic isotope effects with deuterated arene compounds and found that this catalytic hydroarylation is consistent with an electrophilic aromatic substitution process. 相似文献
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