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Coupling biaryl

The very reactive phenyl radical reacts with the aromatic substrate 2, present in the reaction mixture. Subsequent loss of a hydrogen radical, which then combines with 7 to give 4, yields a biaryl coupling product e.g. the unsymmetrical biphenyl derivative 3 ... [Pg.140]

Bergman cycloaromatization 17, 523 f., 528 biaryl coupling -.intramolecular 516f., 519 bicyclic system -, concave face 59 -, convex face 59 bicyclo[3.3.0] system 221 f. bicyclo[4.2.0] system 221 f. bidentate ligands 680 f. [Pg.790]

This iron-ate complex 19 is also able to catalyze the reduction of 4-nitroanisole to 4-methoxyaniline or Ullmann-type biaryl couplings of bis(2-bromophenyl) methylamines 31 at room temperature. In contrast, the corresponding bis(2-chlor-ophenyl)methylamines proved to be unreactive under these conditions. A shift to the dianion-type electron transfer(ET)-reagent [Me4Fe]Li2 afforded the biaryl as well with the dichloro substrates at room temperature, while the dibromo substrates proved to be reactive even at —78°C under these reaction conditions. This effect is attributed to the more negative oxidation potential of dianion-type [Me4Fe]Li2. [Pg.184]

A diastereoselective imine alkylation and a palladium-catalysed biaryl coupling were important steps in the diastereoselective synthesis of 6,7-dihydro-5//-dibenz[c,e]azepines (Scheme 7) starting from (R)-l-(2-methoxyphenyl)ethylamine. Selection for the... [Pg.344]

Albisson DA,Bedford RB, Lawerence SE, Scully PN (1998) Orthopalladated triaryl phosphite complexes as highly active catalysts in biaryl coupling reactions. Chem Commun 2095-2096... [Pg.95]

Bedford RB, Limmert ME, Hazelwood SL, Albisson DA (2002b) Platinum-catalysts for Suzuki biaryl coupling reactions. Organometallics 21 2599-... [Pg.95]

In most cases, construction of axial nonracemic biaryls can be realized by metal-mediated intramolecular biaryl coupling in which the chirality is induced by ort/io-substituted auxiliaries in an aromatic system. [Pg.461]

This biocatalytic method is therefore quite promising for the synthesis of complex molecules. Very recently, it was reported 1121] that HRP catalyzes the oxidation of 2-naphthols to l,l -binaphthyl-2,2 -diols with moderate enantiomeric excess (ee 38-64%) (Eq. 5). However, in view of the analytical techniques used, these data have to be questioned [167]. As shown recently, atrop-selective biaryl coupling can only be achieved by means of dirigent protein as chiral auxiliary [122]. [Pg.90]

Lignans by Chiral Auxiliary-Based Biaryl Coupling. 187... [Pg.185]

Retrosynthetic analysis of 5 and 6 yielded ketone 7 as pivotal intermediate. A key reaction for the synthesis of 7 was the auxiliary-controlled, di-astereoselective biaryl coupling of a phenyl magnesium bromide (from 8 or 9) with aryloxazoline 10 (Scheme 1). This coupling strategy was developed in the Meyers laboratory [12] and previously applied to the enantioselective synthesis of other naturally occurring biaryl lignans, such as steganone [13]. [Pg.187]

Thieno benzazepine 109 was synthesized in moderate yield by oxidative biaryl-coupling using the hypervalent iodine reagent phenyliodine(lll)bis (trifluoroacetate) (FIFA) and BF3 OEt2 as the activating agent in methylene chloride (Equation (16) (2002X8581)). [Pg.20]

Murrayafoline A (7) required for this total synthesis was obtained starting from 3-formylindole (618) (577) (see Scheme 5.40). Lead tetraacetate-mediated oxidative non-phenolic biaryl coupling of 7 led to murrastifoline F (191) in 60% yield. The... [Pg.296]

Acid treatment of a 3 1 mixture of murrayafoline A (7) and koenoline (8) led to chrestifoline A (192) in 70% yield. Addition of murrayafoline A (7) to a mixture of 1057 and lithium aluminum hydride in ether and dichloromethane afforded bismurrayafoline-A (197) in 19% yield (662) (Scheme 5.166). In addition to the aforementioned methods, the same group also reported a stereoselective synthesis of axially chiral bis-carbazole alkaloids by application of their "lactone concept" (663) and a reductive biaryl coupling leading to 2,2 -bis-carbazoles (664). [Pg.297]

The Ullmann coupling is the classical example of Cu-catalyzed biaryl coupling, wherein (a) a phenol and arylhalide substrate are converted to a bis-arylether or (b) two arenes are coupled to form a bis-arene species. These coupling reactions are of great importance for general organic synthesis as well as pharmaceutical and fine chemicals. The copper-catalyzed phenol coupling to arrive at chiral biphenol derivatives is used extensively as a test reaction for the catalytic activity of new copper complexes [254,255]. [Pg.64]

The dihydrooxazol-mediated biaryl coupling of nonracemic 11 with the Grignard reagent derived from l-bromo-2,3,4-trimethoxy-6-methylbenzene yielded (via intermediates of type 12) the two diastereomeric coupling products 13 and 14 in a 6 1 ratio. In this case the relative configuration around the biphenyl axis had to be determined (see p 478)122. [Pg.413]

The low yields in the synthesis of electron-rich biaryls, which are the more frequently occurring natural biaryl targets, are clearly a limitation to this procedure. Further side reactions may arise from hydro-dehalogenation without biaryl coupling, and from intermolecular reactions, leading to dimers or oligomers34,35. [Pg.578]

Kita and Tohma found that exposure of p-substituted phenol ethers to [bis(tri-fluoroacetoxy)iodo]benzene 12 in the presence of some nucleophiles in polar, less nucleophilic solvents results in direct nucleophilic aromatic substitution [Eq. (84)] [156]. Involvement of a single-electron transfer (SET) from phenol ethers to A3-iodane 12 generating arene cation radicals was suggested by the detailed UV-vis and ESR studies. SET was involved in the oxidative biaryl coupling of phenol ethers by 12 in the presence of BF3-Et20 [157]. [Pg.44]

In the intermolecular mode, this reaction has been utilized for the preparation of products 28 from various nucleophiles, including C-nucleophiles (e. g. (3-dicarbonyl compounds). A similar reaction in the intramolecular mode provides a powerful synthetic tool for the preparation of various polycyclic compounds via oxidative biaryl coupling [21,27 - 30]. Several examples of these C-C bond forming reactions are shown in Schemes 13-15. Specifically, various dibenzoheterocyclic compounds 30 have been prepared by the oxidation of phenol ether derivatives 29 with [bis(trifluoroacetoxy)iodo]benzene in the presence of BF3-etherate in dichloromethane (Scheme 13) [27-29]. [Pg.105]

Similar types of nucleophilic substitutions have also been carried out when PIFA is activated by two equivalents of Lewis acids such as trimethylsilyl triflu-oromethanesulfonate (TMSOTf) and BF3 Et20 or heteropolyacid in standard solvents such as CH2C12 and MeCN. These reactions were applied to intramolecular reactions by the same authors leading to biaryls (49) [54-57], quinone imine derivatives (50) [58], and dihydrobenzothiophens (51) [59], which are important structures of bioactive natural products [Eqs. (7)-(9)]. Dominguez and co-workers have expanded the above biaryl coupling reaction to the syntheses of benzo[c]phenanthridine system (52) [60] and heterobiaryl compounds (53) [61] [Eqs. (10,11)]. [Pg.215]

An extension of the intramolecular biaryl coupling with PIFA-BF3 Et20 to a short and efficient access to benzo[c]phenanthridines (60) and phenanthri-... [Pg.236]

Concise total synthesis of a promising antiviral (anti-HIV) agent, michel-lamine A (58), was accomplished by Bringmann and Tasler via oxidative biaryl coupling reaction of korupensamine A (166) using PIFA (or Pb(OAc)4)-BF3 Et20 [128] (Scheme 35). [Pg.237]


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Asymmetric Oxidative Biaryl Coupling Reactions

Biaryl

Biaryl compounds, transition-metal-catalyzed cross-coupling

Biaryl coupling Subject

Biaryl coupling copper-catalysed

Biaryl coupling natural products

Biaryl coupling palladium catalysts

Biaryl cross-coupling

Biaryl phenol coupling

Biaryl phosphines, Suzuki-Miyaura coupling

Biaryl synthesis Negishi coupling

Biaryl synthesis aryl halide reductive coupling

Biarylation

Biaryls

Biaryls by Aryl Coupling

Biaryls formation in phenol ether couplings

Biaryls oxidative coupling, organometallic

Biaryls palladium-catalyzed coupling

Copper catalysts oxidative biaryl coupling

Cross-coupling reactions arene biaryl synthesis

Cross-coupling reactions biaryl synthesis

Group 11 metal-promoted oxidations oxidative biaryl coupling

Homo-coupling reactions of aryl halides to biaryls catalysed by nickel complexes

Homo-coupling reactions of miscellaneous arylmetallic reagents to biaryls

Intramolecular biaryl coupling

Kumada coupling biaryl synthesis

Oxidation biaryl coupling

Oxidative Coupling of Arenes to Biaryl Compounds

Oxidative biaryl coupling

Oxidative couplings of arenes to biaryls and polyaryls

Palladium acetate biaryl couplings

Palladium catalysts biaryl coupling reactions

Palladium catalyzed biaryl coupling

Palladium mediated biaryl coupling

Preparation of biaryls by the Ullmann coupling reaction

Thiophenes biaryl coupling

Ullmann biaryl coupling

Ullmann coupling axially chiral biaryls

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