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Search for "cross-coupling" in Full Text gives 575 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Total synthesis of grayanane natural products
Beilstein J. Org. Chem. 2022, 18, 1707–1719, doi:10.3762/bjoc.18.181
- -membered triflate 71 was synthesized from diketone 26 in 5 steps and 37% overall yield. Both fragments were assembled by a Sonogashira cross-coupling, affording 72 in 72% yield. In a first attempt, TBS protection was considered on the bicylo[3.2.1]octane. However, later in the strategy, the deprotection
Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field
Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179
- introduction of an electron-withdrawing acetoxy group. The DABCO cation radical is less reactive compared to quinuclidine-derived cation radicals. It was involved in the Ni-catalyzed oxidative C–C cross-coupling involving aldehyde C–H bond cleavage with the formation of acyl radicals according to the proposed
- catalyzed by ABNO-type amine-N-oxyl radicals. Hydrogen atom transfer (HAT) and single-electron transfer (SET) as basic principles of amine cation radical oxidative organocatalysis. Electrochemical quinuclidine-catalyzed oxidation involving unactivated C–H bonds. DABCO-mediated photocatalytic C–C cross
- -coupling involving aldehyde C–H bond cleavage. DABCO-derived cationic catalysts in inactivated C–H bond cleavage for alkyl radical addition to electron-deficient alkenes under photoredox catalysis conditions. Electrochemical diamination and dioxygenation of vinylarenes catalyzed by triarylamines
Synthetic study toward the diterpenoid aberrarone
Beilstein J. Org. Chem. 2022, 18, 1625–1628, doi:10.3762/bjoc.18.173
- was further confirmed through X-ray crystallographic analysis. With the key intermediate 10 in hand, we were in a position to test the planned two-step transformation including the palladium-catalyzed reductive cross coupling with HCO2H followed by Pd/C-catalyzed hydrogenation. To our surprise, the
- –Martin oxidation. At this stage, the pivotal C–H insertion step was tried under the reported conditions [34], and cyclopentenone 8 was successfully obtained. Further study with cross coupling or halogen–magnesium exchange shows this moiety is inert for functional group transformation. The attempt for
A new route for the synthesis of 1-deazaguanine and 1-deazahypoxanthine
Beilstein J. Org. Chem. 2022, 18, 1617–1624, doi:10.3762/bjoc.18.172
- the cross coupling reaction. We also mention that we did not decide for a direct transformation [27][28] of 6-iodo-1-deazapurine into 6-hydroxy-1-deazapurine for reasons of solubility and desired regioselectivity of the subsequent nitration reaction. 1-Deazahypoxanthine Synthesis of 1
Simple synthesis of multi-halogenated alkenes from 2-bromo-2-chloro-1,1,1-trifluoroethane (halothane)
Beilstein J. Org. Chem. 2022, 18, 1567–1574, doi:10.3762/bjoc.18.167
- difluoroalkyl ethers (1), along with small amounts of fluoroalkenyl ethers (2), which were obtained from 1 via an E2-elimination mechanism (Scheme 1B) [14][15]. The fluoroalkenyl group in 2 is a potentially useful moiety that could participate in cross-coupling reactions for replacement of the bromine atom with
- HF from 1 provides 2 as an E/Z mixuture (E/Z = 1:1). We speculated that the stability of the E isomer was equal to that of the Z isomer under these conditions. To expand the scope of this reaction, we subjected product 2 to a Sonogashira cross-coupling reaction (Scheme 3). This gave a highly
- functionalized enyne structure that will be useful in various molecular transformations [27][28][29]. On the basis of a previous report, Sonogashira cross-coupling of 2 with trimethylsilylacetylene was performed with a bis(triphenylphosphine)palladium(II) dichloride. The reaction proceeded smoothly to give
An alternative C–P cross-coupling route for the synthesis of novel V-shaped aryldiphosphonic acids
Beilstein J. Org. Chem. 2022, 18, 1518–1523, doi:10.3762/bjoc.18.160
- order of addition of reactants to perform the transition-metal-catalyzed C–P cross-coupling reaction, often referred to as the Tavs reaction, employing NiCl2 as a pre-catalyst in the phosphonylation of aryl bromide substrates using triisopropyl phosphite. This new method was employed in the synthesis of
- three novel aryl diphosphonate esters which were subsequently transformed to phosphonic acids through silylation and hydrolysis. Keywords: arylphosphonic acids; cross-coupling reaction; phosphonate esters; transition-metal catalysis; Introduction Phosphonates and phosphonic acids are a very
- ][25][26]. These catalytic cross-coupling reactions tend to follow similar pathways to the Michaelis–Arbuzov reaction, with the inclusion of a catalytic intermediate step. A number of suitable catalysts have been identified, ranging from nickel(II) bromide and nickel(II) chloride, to palladium(II
Microelectrode arrays, electrosynthesis, and the optimization of signaling on an inert, stable surface
Beilstein J. Org. Chem. 2022, 18, 1488–1498, doi:10.3762/bjoc.18.156
- peptide so that the thiol group in the sidechain could be used to place the molecule the array with the use of an electrochemically initiated Cu(I)-catalyzed cross-coupling reaction (Scheme 1) [9]. To this end, the Cu(I) catalyst needed for the reaction was generated at the electrodes by the reduction of
- for the confinement strategy to keep up. The result is a loss in confinement. It is important to point out that the reaction shown in Scheme 1 is not a typical electrosynthetic reaction. The cross-coupling reaction shown is a Cu(I)-catalyzed transformation that requires no recycling of a reagent
- 12 electrodes each functionalized with pyrene-butanol at various places on the array. For the placement reaction, the Cu(I)-catalyzed cross-coupling reaction used above (Scheme 1) was employed for 4 cycles (90 s on and 180 s off). The chemistry placed enough of the alcohol by the electrodes for the
One-pot synthesis of 2-arylated and 2-alkylated benzoxazoles and benzimidazoles based on triphenylbismuth dichloride-promoted desulfurization of thioamides
Beilstein J. Org. Chem. 2022, 18, 1479–1487, doi:10.3762/bjoc.18.155
- cyclopropanes with arenes [29]. They have also been used in Pd-catalyzed cross-coupling reactions to react with hypervalent iodonium salts, organostananes, and vinyl epoxides [30][31][32]. Moreover, there are reports of them serving as oxidizing agents for alcohols [33]. Two papers have recently reported
Design, synthesis, and evaluation of chiral thiophosphorus acids as organocatalysts
Beilstein J. Org. Chem. 2022, 18, 1471–1478, doi:10.3762/bjoc.18.154
- cross-coupling [34] in excellent yield. Esterification of 6 with monomethyl H-phosphonate tert-butylamine salt [35] resulted in the mixed H-phosphonate ester 7 in excellent yield. Cyclization using our homolytic aromatic substitution methodology [36] gave P-heterocycle 8 in modest yield. Other methods
- cross-coupling, and 2) immobilization on a solid support via reduction and reaction of the aniline with an electrophile such as polystyrene isocyanate. DOPO scaffold We previously reported the syntheses of both enantiomers of 8-phenyl DOPO 3 [38]. The syntheses proceed in only three steps (including the
Synthesis and electrochemical properties of 3,4,5-tris(chlorophenyl)-1,2-diphosphaferrocenes
Beilstein J. Org. Chem. 2022, 18, 1338–1345, doi:10.3762/bjoc.18.139
- transition metal-catalyzed cross-coupling reactions broadly used for the preparation of different diarylacetylenes and, rarely, bis(chlorophenyl)acetylenes. Next, starting substituted benzaldehydes were treated with an excess of SOCl2 for 24 h at 25 °C. Corresponding substituted benzal chlorides 4 were
Modular synthesis of 2-furyl carbinols from 3-benzyldimethylsilylfurfural platforms relying on oxygen-assisted C–Si bond functionalization
Beilstein J. Org. Chem. 2022, 18, 1256–1263, doi:10.3762/bjoc.18.131
- -catalyzed cross-coupling reactions, such as arylation reactions catalyzed by Pd2(dba)3/CuI, as well as allylation and methylation reactions catalyzed by CuI⋅PPh3. C3-Benzyldimethylsilyl-appended furfurals are thus introduced as versatile platforms, providing a modular access to 3-substituted 2-furyl
- on the SiMe(OSiMe3)2 unit, which were readily converted through Pd- or Cu-catalyzed electrophilic substitution reactions into an array of furfurals decorated at C3 with carbon- or heteroatom-containing substituents (Scheme 1). Conversely, all of our subsequent efforts to achieve cross-coupling
- cross-coupling chemistry [30][31], could be accessed from 2-[(3-benzyldimethylsilyl)furyl] carbinols. C3–Si bond functionalization through siloxane formation In an attempt to isolate cyclic siloxane 16, we then considered a protocol reported by Anderson and co-workers to prepare cyclic siloxanes by
Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor
Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115
- (catalyst) separation in one step. The use of a packed bed simplifies the translation of optimized batch reaction conditions to continuous flow, as the only components present in the reaction mixture are the substrate and a base. The metallaphotoredox cross-coupling of sulfinates with aryl halides was used
- systematically study the cross-coupling using the packed-bed reactor, we decided to equip the continuous-flow setup with a dedicated tool for in-line analysis. Such techniques enable rapid investigations of process-related parameters [34]. In particular, the presence of a trifluoromethyl group in the substrate
A Streptomyces P450 enzyme dimerizes isoflavones from plants
Beilstein J. Org. Chem. 2022, 18, 1107–1115, doi:10.3762/bjoc.18.113
- dimers or cross-coupling products, starting from simple monomers [17][18][19]. Nevertheless, our knowledge of enzyme-mediated dimerization is still limited in contrast to the numerous reported dimeric natural products. Phenol coupling in plant polyphenol biosynthesis is one of the earliest documented
Electrochemical formal homocoupling of sec-alcohols
Beilstein J. Org. Chem. 2022, 18, 1062–1069, doi:10.3762/bjoc.18.108
- -coupling reaction of two different benzyl alcohols (Scheme 3). Pleasingly, the reaction using a 1:1 mixture of 1a and 1f under the standard reaction conditions provided the cross-coupling product 2af (dr = 94:6) together with the homocoupling products 2a and 2f. To demonstrate the scalability of the
- /mol, 0 °C, under air. a100 mA cc. b6 F/mol, imidazole (0.075 equiv). c6 F/mol. d8 F/mol, imidazole (0.1 equiv) e8 F/mol, MeCN/MeOH (4:1, 5 mL) without H2O. Investigation of cross-coupling reaction. Large-scale experiment. Control experiments. aDetermined by 1H NMR using 1,3,5-trimethoxybenzene as an
- diastereoselectivity [47]. Benzhydrol derivatives (1n–p) were found to be good substrates for the present reaction, affording the corresponding benzopinacols (2n–p) in good yields after the passage of 8 F/mol in a mixed solvent of MeCN/MeOH. Next, we examined the possibility to extend the present process to the cross
Automated grindstone chemistry: a simple and facile way for PEG-assisted stoichiometry-controlled halogenation of phenols and anilines using N-halosuccinimides
Beilstein J. Org. Chem. 2022, 18, 999–1008, doi:10.3762/bjoc.18.100
- halides are valuable compounds with potent bioactivities [1][2][3][4][5] (Figure 1) and are utilized as crucial precursors for various metal-catalyzed cross-coupling reactions [6][7][8][9]. They are frequently used as synthetic intermediates in several value-added syntheses of natural products
- of monoiodo derivatives was successfully prepared in high to excellent yields from phenols and anilines by adding 1.1 equiv of NIS with PEG-400 as the LAG agent (product 2aa–ag, Scheme 3). Notably, both Br- and I-substituents are mainly used as the substrates for cross-coupling reactions indicating
Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials
Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94
- [34], dibromodithienothiophene 24 is lithiated with n-butyllithium at −90 °C, and the resulting species is reacted in situ with triisopropyl borate. After aqueous workup, dithieno[3,2-b:2’,3’-d]thiophene-2,6-diylboronic acid (25) is obtained, enabling subsequent Suzuki–Miyaura cross-coupling [36
- ]. This palladium-catalysed cross coupling is preferred over a Stille cross-coupling due to the high toxicity of organotin reagents [37]. Moreover, purification of compound 25 is facile since it can be used for further reactions after re-precipitation in petroleum ether. In a manner similar to [35], it is
- possible to convert 25 into the corresponding pinacol ester, 2,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)dithieno[3,2-b:2’,3’-d]thiophene (26) by stirring 25 with pinacol in refluxing toluene, but this has no beneficial impact on the subsequent cross-coupling. Compound 26 has been published
On Reuben G. Jones synthesis of 2-hydroxypyrazines
Beilstein J. Org. Chem. 2022, 18, 935–943, doi:10.3762/bjoc.18.93
- , respectively. Shifts (δ) are given in ppm with respect to the TMS signal and cross-coupling constants (J) are given in hertz. Column chromatography was performed either on Merck silica gel 60 (0.035–0.070 mm) or neutral alumina containing 1.5% of added water using a solvent pump and an automated collecting
Synthetic strategies for the preparation of γ-phostams: 1,2-azaphospholidine 2-oxides and 1,2-azaphospholine 2-oxides
Beilstein J. Org. Chem. 2022, 18, 889–915, doi:10.3762/bjoc.18.90
- -oxides 42 and 44 in moderate 54–63% yields via the intramolecular copper-catalyzed cross-coupling of ethyl/benzyl 2-bromobenzylphosphonamidates 41 or P-(2-bromobenzyl)-P-(methyl)phosphinamide (43) as a key step. They were prepared from 2-bromobenzyl bromide (38) via three and four steps, respectively
Synthesis of novel alkynyl imidazopyridinyl selenides: copper-catalyzed tandem selenation of selenium with 2-arylimidazo[1,2-a]pyridines and terminal alkynes
Beilstein J. Org. Chem. 2022, 18, 863–871, doi:10.3762/bjoc.18.87
- selenides [25]. In this reaction, unlike the former, bis(imidazo[1,2-a]pyridin-3-yl) diselenides are generated through C–H selenation at the 3-position of 2-arylimidazopyridines with Se powder, followed by the cross-coupling reaction between diselenides and triarylbismuthines. These one-pot reactions are
- imidazopyridinyl selenides A Cu-catalyzed cross-coupling reaction using benzene ring substituted diaryl diselenides with terminal alkynes in the presence of bases is effective for synthesizing aryl alkynyl selenides [27][28][29][30][31]. We previously reported a simple method for the synthesis of bis(2-arylimidazo
Palladium-catalyzed solid-state borylation of aryl halides using mechanochemistry
Beilstein J. Org. Chem. 2022, 18, 855–862, doi:10.3762/bjoc.18.86
- , Japan 10.3762/bjoc.18.86 Abstract This study describes the solid-state palladium-catalyzed cross-coupling between aryl halides and bis(pinacolato)diboron using ball milling. The reactions were completed within 10 min for most aryl halides to afford a variety of synthetically useful arylboronates in
- mill; borylation; cross-coupling; mechanochemistry; solid-state reaction; Introduction Arylboronic acid and its derivatives are indispensable reagents in modern synthetic chemistry because they have been frequently used for the preparation of many bioactive molecules, natural products, and functional
- transformations. Thus far, mechanochemical palladium-catalyzed cross-coupling reactions such as Suzuki–Miyaura [34][35][36][37][38][39][40][41][42][43][44][45][46][47], Buchwald–Hartwig [48][49][50][51][52], Sonogashira [53][54][55][56], Negishi [57], Mizoroki–Heck [58][59][60], and C–S bond-forming [61
Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies
Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70
- decarboxylation of the malonic acid derivative 42 to give pent-4-enecarboxylic acid (43). In many cases, the flow protocol provided improved yields compared to the corresponding batch syntheses. Palladium-catalyzed cross-coupling reactions require higher temperatures and thus can be realized in an inductively
- catalysis can be generated directly by the functionalized nanostructured particles (Scheme 12, case C) [50]. This was achieved by reductive precipitation of Pd(0) nanoparticles from ammonium-bound tetrachloropalladate [84][85], which showed good catalytic activity in various cross-coupling reactions under
Mechanochemical halogenation of unsymmetrically substituted azobenzenes
Beilstein J. Org. Chem. 2022, 18, 680–687, doi:10.3762/bjoc.18.69
- ; N-halosuccinimide; palladium(II); Introduction Electrophilic aromatic substitution [1][2][3] and ligand-directed transition-metal-catalyzed reactions [4][5][6][7][8] are among the most widely used synthetic approaches for the preparation of halogenated arenes. They are important precursors in cross
- -coupling reactions [9][10][11][12][13][14][15][16][17][18][19] or components of pharmaceuticals and biologically active molecules [20][21]. The synthetic aspects of both approaches in solution are well established. The need for green and sustainable chemistry [22] has led to the development and synthetic
DDQ in mechanochemical C–N coupling reactions
Beilstein J. Org. Chem. 2022, 18, 639–646, doi:10.3762/bjoc.18.64
- as C–P [17], C–O [18][19][20], and C–S [21] were achieved using DDQ as an oxidant [22][23]. In addition, the utilization of DDQ as a photoredox catalyst [24] and co-catalyst [25][26] have also been documented in organic synthesis [27]. DDQ-mediated oxidative C–N cross-coupling reactions are well
- direct C–H amination is vital to provide many amine derivatives by sustainable methods [36][37]. The dehydrogenative C–N cross-coupling reactions from unreactive N–H and C–H bonds can lead to various nitrogen-containing heterocycles [32][38]. Herein, we disclose the DDQ-mediated oxidative C–N coupling
- , followed by hydride abstraction to generate the desired product 2a. On the other hand, the formation of quinazolin-4(3H)-ones starts with the formation of an imine intermediate and then it will follow the similar mechanistic pathway. To explore the synthetic utility of the oxidative C–N cross-coupling
Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis
Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62
- + 26), respectively, were successfully employed as visible-light photocatalysts for a cross-coupling cyclization of N,N-dimethylaniline (27) and N-alkyl/aryl maleimides 28 (Figure 6). Notably, the systems showed much higher catalytic activity compared to similar reactions with the dye or cages alone
Substituent effect on TADF properties of 2-modified 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methylpyrimidines
Beilstein J. Org. Chem. 2022, 18, 497–507, doi:10.3762/bjoc.18.52
- of aryl moieties into methylthio-substituted nitrogen heterocycles such as tCBz-mPYR are a Ni(0)-catalyzed cross-coupling reaction with Grignard reagents [34][36] or the Liebeskind–Srogl reaction employing arylboronic acids [37][38][39]. Taking into account a large assortment of arylboronic acids and
- the simplicity of the method, we chose the Liebeskind–Srogl cross-coupling reaction for the synthesis of the target 2-arylpyrimidine derivatives. Thus, heating tCbz-mPYR with phenyl-, 4-cyanophenyl-, 3-cyanophenyl-, or 3-bromophenylboronic acid at 130 °C in dioxane in the presence of Pd(PPh3)4, copper
- pyrimidine–carbazole TADF emitters bearing different substituents in position 2 of the pyrimidine moiety were successfully prepared by using Liebeskind–Srogl cross-coupling, hydrogenolysis, oxidation reactions of 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methyl-2-methylthiopyrimidine and following
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