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Search for "electrophilic" in Full Text gives 677 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Carbonylative synthesis and functionalization of indoles
Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87
- heterocyclization reactions by exploiting the electrophilic character of Pd(II) species. Starting from substrates bearing a triple bond and a nucleophile in the appropriate position, a versatile process of heterocyclization can be initiated, resulting in indole derivatives with important properties. Gabriele et al
Enantioselective synthesis of β-aryl-γ-lactam derivatives via Heck–Matsuda desymmetrization of N-protected 2,5-dihydro-1H-pyrroles
Beilstein J. Org. Chem. 2024, 20, 940–949, doi:10.3762/bjoc.20.84
- products) were found to be somehow unstable when concentrated to dryness during work-up. We hypothesize that a possible cause of such instability might consist in the formation of a highly electrophilic iminium ion upon protonation of the hemiaminal ether by silica or glassware acidity and further
Direct synthesis of acyl fluorides from carboxylic acids using benzothiazolium reagents
Beilstein J. Org. Chem. 2024, 20, 921–930, doi:10.3762/bjoc.20.82
- from a self-propagating process initiated by addition of an adventitious nucleophile to the electrophilic thioester. This results in elimination of a (trifluoromethyl)thiolate (−SCF3) anion (C, Scheme 4), which can subsequently undergo β-fluoride elimination, releasing a fluoride anion. Addition of F
- highly electrophilic compound can react with the carboxylic acid in the presence of DIPEA via addition/elimination affording a thioic anhydride species E and a fluoride ion [9]. Addition of F− to the carboxyl carbon followed by fluoride elimination from the resulting thiocarboxylate would provide acyl
Synthesis and properties of 6-alkynyl-5-aryluracils
Beilstein J. Org. Chem. 2024, 20, 898–911, doi:10.3762/bjoc.20.80
- functional groups adjacent to them, due to withdrawing effects. Chlorine has a stronger electron-withdrawing effect than bromine, so the electrophilic character of the 6-position should be higher than that of the 5-position. However, it is unlikely to be the only reason for the formation of just one
(Bio)isosteres of ortho- and meta-substituted benzenes
Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78
- was developed by Anderson and co-workers and was shown to be the more versatile than initiator-free activation. Both initiator-free and Et3B-initiated reactions only tolerated electrophilic radicals (to 134a and 134e), while photoredox catalysis also tolerated electron-rich radicals (to 134b). The
- -workers, and was accessed over 8 steps from diene 161 (Scheme 17A) [51]. Diels–Alder reaction of diene 161 and di-tert-butyl azodicarboxylate (160) followed by palladium-assisted elimination of acetic acid gave diene 162. A sequence of 4π-electrocyclisation and electrophilic transcarbamation (to 163
Ortho-ester-substituted diaryliodonium salts enabled regioselective arylocyclization of naphthols toward 3,4-benzocoumarins
Beilstein J. Org. Chem. 2024, 20, 841–851, doi:10.3762/bjoc.20.76
- . Keywords: annulation; arylocyclization; 3,4-benzocoumarin; diaryliodonium salts; naphthol; Introduction Diaryliodonium salts as electrophilic reagents have attracted significant attention in the field of organic synthesis owing to their efficiency and selectivity [1][2][3][4][5][6][7]. Particularly, they
- , expanding the benzocoumarin family (Scheme 1b) [14]. Recently, ortho-functionalized diaryliodonium salts, due to their coordinating and electrophilic effects, have exhibited unique reactivity and chemoselectivity [15]. As such, a wide range of functional groups including the trimethylsilyl group, boronic
Skeletal rearrangement of 6,8-dioxabicyclo[3.2.1]octan-4-ols promoted by thionyl chloride or Appel conditions
Beilstein J. Org. Chem. 2024, 20, 823–829, doi:10.3762/bjoc.20.74
- the glycosidic bond using an organometallic purine or pyrimidine derivative and an electrophilic furanose derivative [23][25]. This process can result in anomeric mixtures, so 5 has potential applications in targeted synthesis, as the configuration of the pseudo-anomeric centre matches the common
- the displacement of the chloro substituent with the allyl group, affording 21 in good yield. Electrophilic aromatic substitution reactions at the chloroalkyl ether site were possible when promoted by aluminium chloride, with anisole and diphenyl ether giving addition products 22 and 23 containing
Palladium-catalyzed three-component radical-polar crossover carboamination of 1,3-dienes or allenes with diazo esters and amines
Beilstein J. Org. Chem. 2024, 20, 661–671, doi:10.3762/bjoc.20.59
- electrophilic trapping of onium ylides generated from metal carbenes with nucleophiles, providing an ingenious difunctionalization strategy for diazo compounds to access structurally complex and diverse molecules (Scheme 1b, top) [28][29]. In recent years, radical-mediated MCRs with diazo compounds have become
Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination
Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43
- ), a supporting ligand that would be predicted to create more electrophilic gold due to its high π-acceptor properties, major decomposition was observed for the slower substrates (1b and 1c) and the fast urea (1a), indicating catalysts that are much more prone to decomposition, and preventing any
- electrophilic enough to activate alkenes toward the attack of pyrroles [34][35]. Gold-catalyzed reactions are known to be sensitive to subtle anion and media effects [48], and within the binary of rate determining π-activation versus protodeauration, trends do not always provide obvious conclusions. The unique
Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas
Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41
- generate a fluoride ion that facilitates limiting enolization processes, and an electrophilic N–F fluorinating agent that is reactive towards neutral enol species. Keywords: difluorination; difluoromethylene; direct fluorination; electrophilic fluorination; organofluorine; Introduction Fluorine is
- fluorodesulfurizations of carbonyl derivatives using a combination of sources of halonium and fluoride ions such as 1,3-dibromo-5,5-dimethylhydantoin (DBH) and tetrabutylammonium dihydrogen trifluoride have been achieved [9][10][11]. The transformation of methylene to difluoromethylene using electrophilic fluorinating
- agents offers an alternative fluorination route, for example, the reactions of MeCN solutions of 1,3-diketones with electrophilic fluorinating agents such as Selectfluor eventually give the corresponding 2,2-difluoro-1,3-diketone derivatives [12]. Monofluorination of the 1,3-diketone substrates is rapid
Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles
Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36
- pharmaceutical and biological activities. Among indole derivatives, bis(indolyl)methanes (BIMs) are profoundly interesting, due to their wide range of pharmaceutical properties. The most common approach involves the electrophilic substitution of various aldehydes and ketones by indoles, utilizing either protic
- . The difference between the two mechanistic pathways is the nature of activation of the carbonyl group. Protic acids induce the protonation of the carbonyl group of the aldehyde or ketone, enhancing its electrophilic character. Whereas, Lewis acid catalysts bind to the heteroatom of the carbonyl group
- research group explored the activity of cadmium sulfide (CdS) nanotubes as heterogeneous nanocatalysts for the electrophilic condensation between aldehydes and indoles [106]. The nanorods were obtained with a solvothermal technique, where thiourea and cadmium nitrate were mixed in ethylenediamine for 10
Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines
Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34
- electrophilic center C(1) of 1 is much lower. It comes, therefore, with no surprise that the interaction of arylamines and the 5-hydroxy and 5-acetoxy derivatives of 3H-phenoxazin-3-one is directed toward the C(2) reaction center to yield 2-amino-3H-phenoxazin-3-ones as the final products under aerobic
- formation [6]. In turn, without an acidic catalyst, it is driven by the distribution of the electron density (Figure 1), such that the nucleophilic attack occurs at the most electrophilic C(2) center. With this in mind, we presented a convenient procedure for the SNH reaction of aromatic amines with
Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments
Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30
- synthesis and a final closure of the 7-membered ring by C–C bond formation. This is in sharp contrast with the widely adopted strategy relying on the late-stage insertion of the sulfur atom with concomitant ring closure, using either electrophilic or nucleophilic sulfur reagents. By way of example, thiepine
- depicted in Scheme 14, the 12-membered ring orifice of fullerene 51 was first enlarged by electrophilic addition of sulfur. After encapsulation of H2 molecule(s) (n = 1 or 2), four synthetic steps were required to reduce the hole size and ultimately obtain cage-closed compound (H2)n@54. In order to remove
Nucleophilic functionalization of thianthrenium salts under basic conditions
Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26
- % yield (Scheme 4). This operationally simple protocol enables the rapid development of novel thioetherification reactions using bench-stable alkylthianthrenium salts as the electrophiles. As is well known, alkyl trifluoromethanesulfonate (alkyl-OTf), serving as a potent electrophilic reagent, can also
- engage in reactions with electrophilic reagents like thiophenol or amines under alkaline conditions, facilitating the formation of respective C–N/O bonds. The synthesis of alkylthianthrenium salts requires alkyl trifluoromethanesulfonate as a precursor, which can also act as an electrophile. However
Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination
Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24
- of quinoquinolines, their planar structure, and very easy coordination to acidic and electrophilic sites (including water [15][22] or the C–H bond of chloroform [11]) almost always lead to co-crystallization. For example, there is no such crystallographic information for quinoquinoline 3 itself. In
- , dipyridoacenaphthene 5 is not brominated by molecular bromine in chloroform or acetic acid. The action of the NBS–DMF system, previously proposed for the electrophilic bromination of alkylaromatic compounds [26], leaves substrate 5 unchanged at room temperature, and when heated to 75 °C for several days causes its
- assumed admixture 11. Mononitration of compound 5. Dehydrogenation of compounds 10 and 11. Nucleophilic methoxylation of compounds 10(12). Electrophilic bromination of compound 5. tele-Elimination upon interaction of dibromide 15 with pyrrolidine. Interaction of dibromide 15 with anionic bases. Comparison
Tandem Hock and Friedel–Crafts reactions allowing an expedient synthesis of a cyclolignan-type scaffold
Beilstein J. Org. Chem. 2024, 20, 162–169, doi:10.3762/bjoc.20.15
- are excellent substrates for such reactions, affording electrophilic carbonyl derivatives susceptible to react with nucleophiles in the acidic reaction mixture [4][5][6][7][8]. Consequently, the Hock rearrangement is likely to be part of tandem processes involving this carbonyl function [9][10][11
- methide intermediate 9 upon elimination of the hydroxy group. This highly electrophilic species could trigger a second intramolecular Friedel–Crafts reaction leading to 6. The cyclic connectivity of 6 was determined by bidimensional NMR experiments, incidentally showing a broadening of the signals of
Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides
Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14
- intermediate C is then generated, followed by the combination of the bromine anion with intermediate B. Finally, selective C5 bromination is accomplished via aromatic electrophilic substitution of 1a with intermediate C promoted by the copper catalyst to afford the desired product 3aa. Conclusion In summary
Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes
Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13
- equivalents of TCNEO relative to the alkyne substrate for the generation of the TCBD products [100]. For the reaction, the formal [3 + 2] cycloaddition reaction is postulated to initiate through the initial nucleophilic attack of the alkyne carbon on the electrophilic TCNEO carbon, yielding a zwitterionic
Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes
Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145
- carbenes available to the chemist [7]. Among them, the cyclic (alkyl)(amino)carbenes (CAACs, E) introduced by Bertrand et al. in 2005 [8] have attracted a great deal of attention, thanks to their remarkable nucleophilic (σ-donating) and electrophilic (π-accepting) properties, which allow them to activate a
Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks
Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127
- . Hydrazones can be regarded as electrophilic and nucleophilic imine equivalents, and thus they represent valuable and versatile building blocks in synthetic chemistry [32][33][34][35][36]. Trifluoroacetaldehyde hydrazones can be regarded as an equivalent of fluorine-containing azomethine imines in the
- =N motif within hydrazones gives them both electrophilic and nucleophilic character. In 2005, Brigaud et al. developed a highly stereoselective method for the synthesis of α-trifluoromethylamines with organometallic reagents to extend the asymmetric methodologies of trifluoroacetaldehyde hydrazones
Unprecedented synthesis of a 14-membered hexaazamacrocycle
Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126
- the most electrophilic C2 carbon of the pyrimidine ring in 8 to give intermediate A. Cleavage of the C2–N3 bond in the latter followed by proton transfer in the formed zwitterion B affords bis-amidrazone C. Next, two molecules of bis-amidrazone C react with each other forming adduct D, which either
Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups
Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125
- electrophilic character of C7. In both hdz-CH3 and hdz-NO2, methoxy hydrogens occur as a pair of singlets: H15 and H17 at 3.88 ppm, and H16 at 3.74 ppm. Methyl H18 in hdz-CH3 appears as a more shielded singlet at 2.22 ppm. Regarding the aromatic region of this compound, the doublet related to H6 (7.28 ppm) is
N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations
Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106
- organosulfur chemistry, sulfenylating agents are an important key in C–S bond formation strategies. Among various organosulfur precursors, N-sulfenylsuccinimide/phthalimide derivatives have shown highly electrophilic reactivity for the asymmetric synthesis of many organic compounds. Hence, in this review
- bonds of unactivated aryls or aromatic sulfenylation by electrophilic aromatic substitution (SEAr) has also recently received attention [38]. In recent years, N-(aryl/alkylsulfenyl)succinimides and N-(arylsulfenyl)phthalimides have been widely employed as new alternative sulfenylating reagents in the
- field of organic synthesis. These compounds are readily accessible, safe, and more stable than toxic, unstable, and foul-smelling thiols. These electrophilic sulfur sources have deserved particular interest for the C–S bond formation via the reaction with various nucleophiles. Their preparation is
Cyclization of 1-aryl-4,4,4-trichlorobut-2-en-1-ones into 3-trichloromethylindan-1-ones in triflic acid
Beilstein J. Org. Chem. 2023, 19, 1460–1470, doi:10.3762/bjoc.19.105
- conjugated enones afford O,C-diprotonated forms under superelectrophilic activation conditions. These dications can participate in electrophilic aromatic substitution reactions with arenes ([11] and references therein). Recently, we have shown that the reaction of (E)-5,5,5-trichloropent-3-en-2-one [Cl3CCH
- form of the starting compound [Cl3CCH=CHC(=OH+)Me]. The presence of two strong electron-withdrawing substituents, the trichloromethyl group (CCl3) and a protonated carbonyl (C(OH+)Me), at the carbon–carbon double bond makes this O-protonated species electrophilic enough to react with arenes (Scheme 1a
- ). The second protonation of the C=C bond is hampered due to a strong acceptor character of the substituents, contrary to other more donating enones. As a continuation of the research on the electrophilic activation of electron-poor alkenes bearing two electron-withdrawing substituents at the C=C bond
α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping
Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103
- protodemetalation to provide ultimately the 1,4-addition adduct. In the presence of carbonyl acceptors, aldol condensation occurs providing overall a tandem 1,4-addition–aldol process. When a tert-butanesulfinyl moiety is present on the nitrogen atom, these electrophilic substitution reactions occur with good
- regardless of its nitrogen substitution; the outcome of the reaction is a tandem 1,4-addition–aldol process. When the tert-butanesulfinyl moiety is present on the nitrogen atom, electrophilic substitution of the intermediate enolates (protodemetalation or aldol condensation) occurs with decent levels of
- is poised to undergo β-fragmentation, but this process can be outcompeted by in situ electrophilic substitution reactions which offer synthetically useful procedures: 1,4-addition (for substrates having N–H bonds) or tandem 1,4-addition–aldol reactions (in the presence of carbonyl electrophiles
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