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Search for "organocatalyst" in Full Text gives 144 result(s) in Beilstein Journal of Organic Chemistry.
Vinylogous functionalization of 4-alkylidene-5-aminopyrazoles with methyl trifluoropyruvates
Beilstein J. Org. Chem. 2025, 21, 533–540, doi:10.3762/bjoc.21.41
- [32]. Then, we increased the reaction scale to 0.2 mmol and obtained similar results (Table 1, entry 13). At this point, we decided to explore the use of a bifunctional organocatalyst in order to improve the yield. When squaramide SQ-1 was used as a catalyst, we observed a similar yield and
Organocatalytic kinetic resolution of 1,5-dicarbonyl compounds through a retro-Michael reaction
Beilstein J. Org. Chem. 2025, 21, 473–482, doi:10.3762/bjoc.21.34
- organocatalytic synthesis of 2-cyclohexen-1-ones via a Michael/Michael/retro-Michael cascade reaction [31]. Our research has shown that the Jørgensen–Hayashi catalyst [32][33] is a highly promising organocatalyst, facilitating enantioselective Michael addition reactions with high yields and excellent levels of
- to enamine E, which epimerizes at C-4 and, after hydrolysis, provides the adduct syn-(3R,4R)-1 with an initial er of 4:96. This diastereoselective epimerization phenomenon promoted by an organocatalyst has not been previously described. The study emphasizes the reversibility of some organocatalyzed
- reactions and their impact on the enantioselectivity and diastereoselectivity of the products. The results show that Michael adducts can evolve from enantioenriched mixtures to racemic ones in the crude reaction while in contact with the chiral organocatalyst. Conclusion The first example of the
Recent advances in organocatalytic atroposelective reactions
Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6
- been prepared, which aims to provide an update on the last five years of this burgeoning area with some relevant links to key earlier works. The material in this article is divided according to the major activation mode of the organocatalyst, from covalent activation via enamine and iminium activation
- organocatalytic Michael addition to alkynals 2 (Scheme 1) [18]. The authors identified the Jørgensen–Hayashi-type catalyst C1 as the most efficient organocatalyst. In this way, a range of axially chiral styrenes were obtained in high yields and enantiomeric purities. The reaction was based on an iminium
- activation of propargylic aldehydes with catalyst Int-1. Another critical feature was the ability of the organocatalyst to promote the Z-selective isomerization of Int-2 to Int-3. In a related fashion, Wang and co-workers developed an atroposelective heterocycloaddition [19]. The iminium-activated alkynals 4
Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines
Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268
- their structure will be described. In 2012, Wang and co-workers reported a bifunctional thiourea-catalyzed aza-Diels–Alder reaction of cyclic keto/enolate salts 1 and N-tosyl-2-methylene-but-3-enoates 2 (Scheme 1). After a screening of the reaction conditions they found that organocatalyst I, acetic
- organocatalyst acts as a Lewis base forming an enamine which raises the HOMO energy of the dienophile, while the thiourea moiety acts as a Lewis acid, lowering the LUMO level of the diene (Scheme 1). A confined transition state is formed providing a high enantiocontrol of the reaction. In 2016, Shi and co
- ) and good to excellent enantioselectivities (60–97% ee) when using organocatalyst III. Later, in 2018, Zhou and co-workers developed a bifunctional squaramide-catalyzed enantioselective formal [4 + 2] cycloaddition of benzofuran-derived azadienes 11 with malononitrile (12) [26]. This work provides an
Advances in the use of metal-free tetrapyrrolic macrocycles as catalysts
Beilstein J. Org. Chem. 2024, 20, 3085–3112, doi:10.3762/bjoc.20.257
- state stabilizes the anionic species generated during the reaction pathway and facilitates a backside attack of I− on the epoxide thus resulting in the initial ring opening (Figure 4b). Apart from acting as an organocatalyst, calix[4]pyrrole 11 has been used for the promotion of cuprous chloride
- monomer. Since the aggregates were found catalytically inactive, while the monomers in the solution were active, the system acts as a pH-switchable ‘ON–OFF’ organocatalyst. In the case of the enamine-mediated addition of cyclohexanone (62) to 4-nitrobenzaldehyde (7), using 10 mol % of 58 provided up to 99
- % yield with a 93:7 ratio of the anti:syn aldol product (63a:63b) and no enantioselectivity at pH 6.7, whereas at pH 3.6 the catalyst was completely inactive (Table 4). Although the supramolecular system composed of a porphyrin macrocycle and a secondary amine organocatalyst operated through the
5th International Symposium on Synthesis and Catalysis (ISySyCat2023)
Beilstein J. Org. Chem. 2024, 20, 2704–2707, doi:10.3762/bjoc.20.227
- organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen”, an interesting approach to recycling the very useful cinchona squaramide organocatalysts was described. This approach involved functionalization of the organocatalyst with a lipophilic linker (octadecyl side chains), resulting in a
- novel lipophilic cinchona squaramide organocatalyst. This organocatalyst was evaluated in a benchmark Michael addition of acetylacetone to trans-β-nitrostyrene, yielding the Michael adduct with high yield and enantioselectivity. The hydrophobic chain of the catalyst allowed the organocatalyst to be
- time-consuming, complex, and expensive. Consequently, it is of utmost interest to immobilize them for reuse but without affecting their catalytic activity. The main factors discussed were the type of support, immobilization, and interaction between the support and the organocatalyst. The particular
Asymmetric organocatalytic synthesis of chiral homoallylic amines
Beilstein J. Org. Chem. 2024, 20, 2349–2377, doi:10.3762/bjoc.20.201
- the asymmetric addition of organoboron reagents to imines (Scheme 3). An intermolecular hydrogen bonding between a non-rigid organocatalyst and a non-rigid substrate was shown to play a key role in assembling a configurationally stable transition structure. As a result, this approach unveiled the
- highly enantioselective nucleophilic addition of primary (10), secondary, and even tertiary allylboronates, as well as allenylboronates to a broad set of imines, bearing the N-phosphinoyl group. The new approach allowed the activation of both the substrate and the reagent using aminophenol organocatalyst
- equiv of isatin with a 50% excess of the α-CF3-substituted imine in toluene at room temperature in the presence of 10 mol % of organocatalyst 138 for times between 1 and 80 h. The reaction exhibited a broad scope in the isatin carbonate derivatives with high to excellent enantioselectivities (89–99
Catalysing (organo-)catalysis: Trends in the application of machine learning to enantioselective organocatalysis
Beilstein J. Org. Chem. 2024, 20, 2280–2304, doi:10.3762/bjoc.20.196
- , Corminboeuf and co-workers reported OSCAR, a computational repository of 4,000 organocatalyst structures mined from the literature and Cambridge Structural Database (CSD) [31]. In addition, the authors utilised the combinatorial nature of organocatalysts to create data bases comprising more than 8,000 NHC
- -type catalysts and more than one million double hydrogen bond donor catalysts. While this repository does not provide any reactivity data, it still comprises a valuable map of organocatalyst chemical space to aid in catalyst design. The creation of these larger datasets, both experimental and in silico
- including pyrimidines and pyrazines. The importance of mechanistic understanding for model building was underlined by Kuang et al. [126], where the authors considered multi-catalyst enantioselective reactions, where one catalyst was an organocatalyst, either CPA or an amine. The co-catalyst was included in
Factors influencing the performance of organocatalysts immobilised on solid supports: A review
Beilstein J. Org. Chem. 2024, 20, 2129–2142, doi:10.3762/bjoc.20.183
- supported organocatalyst whose catalytic efficiency can be reproduced over a sufficient number of reaction cycles. Despite the difficulty of the challenge, the design of heterogeneous, recyclable organocatalytic systems is of high interest [8]. The continued development of efficient catalytic recovery
- Amorphous (SBA-15) and small pore-sized Mobil Composition of Matter (MCM-41) were applied and compared as supports of an organocatalyst. These silicas were modified by incorporating an organosulfonic acid group (propylenesulfonic acid) through a post-synthesis grafting method. Their catalytic performance
- lead to a decrease in selectivity. Connon and co-workers have attached a cinchona thiourea organocatalyst to magnetic nanoparticles 13 for the Michael addition of dimethyl malonate (10) to trans-β-nitrostyrene (11) (Scheme 3) [31]. To explore the potential impact of nanoparticles on catalyst efficiency
Mechanistic investigations of polyaza[7]helicene in photoredox and energy transfer catalysis
Beilstein J. Org. Chem. 2024, 20, 1236–1245, doi:10.3762/bjoc.20.106
- increased when the triplet efficiently reacts in a catalytic cycle such that turnover numbers exceeding 4400 are achievable with this organocatalyst. Keywords: energy transfer; laser spectroscopy; organocatalyst; photoredox; time-resolved spectroscopy; Introduction The emergence of photoredox chemistry in
Methodology for awakening the potential secondary metabolic capacity in actinomycetes
Beilstein J. Org. Chem. 2024, 20, 753–766, doi:10.3762/bjoc.20.69
- in the genetically programmed death of the producing organism. In addition, Nishiyama et al. suggested that actinorhodin (8) produced by Streptomyces coelicolor A3(2) functions as an organocatalyst to kill bacteria by catalyzing the production of toxic levels of H2O2 [99]. They also suggested that
Evaluation of the enantioselectivity of new chiral ligands based on imidazolidin-4-one derivatives
Beilstein J. Org. Chem. 2024, 20, 684–691, doi:10.3762/bjoc.20.62
- chiral metal complex catalyst but also as an enantioselective organocatalyst [17]. Accordingly, its application in enantioselective organocatalysis, particularly in asymmetric reactions through “enamine activation”, warrants further investigation. Results and Discussion The corresponding copper(II
- , the configuration of a ligand at position 2 determines the type of enantiomer of nitroaldol in excess and the environment around the stereogenic centre at position 5 affects the resulting value of ee. The structure of compound IV is similar to the well-known organocatalyst 5-(S)-pyrrolidin-2-yl-1H
- acids producing chiral isotetronic acids. However, the application of compound IV as the organocatalyst in these reactions proceeded sluggishly, and the corresponding products were obtained in only moderate ees [24]. Herein, the aldol reaction was chosen as a standard asymmetric reaction to explore the
Switchable molecular tweezers: design and applications
Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45
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
- organocatalyst (Scheme 13) [95]. Haloalkynes have the ability to form strong, directional and selective halogen bonds, which makes them a good choice for the synthesis of BIMs [95]. Several substituted carbonyl compounds, as well as indoles, were screened in the optimum reaction conditions as seen in Scheme 13
Photochromic derivatives of indigo: historical overview of development, challenges and applications
Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23
- substituents in the isatin ring showed pronounced negative photochromism upon irradiation with red light (625−650 nm). Supramolecular complexation with Schreiner’s thiourea organocatalyst (STC) allowed to reach better conversion with the isomeric ratio in PSS increased from 46% to 84%. The backward switching
- organocatalyst (STC). Photoisomerization of the protonated isoindigo. Absorption maxima of indigo and its derivatives in C2Cl4 at 20 °C [23][24]. Photophysical and photochemical characteristics of N-aryl- N'-alkylindigos [42][66].
A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen
Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133
- , application, and recycling of a new lipophilic cinchona squaramide organocatalyst. The synthesized lipophilic organocatalyst was applied in Michael additions. The catalyst was utilized to promote the Michael addition of cyclohexyl Meldrum’s acid to 4-chloro-trans-β-nitrostyrene (quantitative yield, up to 96
- homogeneous reaction. For example, by incorporating a lipophilic side chain [28] on the organocatalyst that does not interfere with its catalytic activity thanks to a linker between the catalyst and lipophilic units. In this way, a significant difference in polarity can be achieved between the catalyst and
- the other components of the reaction mixture. The lipophilic O-alkylated gallic acid unit increases the solubility of the organocatalyst in less polar solvents, such as DCM or toluene but leads to the precipitation of the organocatalyst in polar solvents, including MeOH or MeCN. As a result, the
Synthesis of 5-arylidenerhodanines in L-proline-based deep eutectic solvent
Beilstein J. Org. Chem. 2023, 19, 1537–1544, doi:10.3762/bjoc.19.110
- Knoevenagel condensation of rhodanine with different aldehydes [3]. The reactions were performed in ChCl/urea (1:2) at 90 °C, without needing a catalyst and the products were obtained in low to good yields (10–78%). On another hand, ʟ-proline is well known as an organocatalyst and its use in aldol and
N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations
Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106
- catalytic amount of Et3N. Moreover, mono-sulfenylation of α-methyl-γ-phenyl-substituted butenolide at α-position was carried out in the presence of Et3N as well as quinine organocatalyst and products were obtained in high yields. In addition to the use of N-(alkyl/arylthio)succinimides in the sulfenylation
- ) by using an organocatalyst was reported by Wang and co-workers (Scheme 35) [67]. Several orgnocatalysts, such as piperidine, and pyrrolidine derivatives were evaluated for the coupling reaction, in which pyrrolidine trifluoromethanesulfonamide A was selected as the best catalyst for this purpose. It
- sulfur reagents resulted in thiolated products 92 up to 99% ee, in the presence of quinidine as the organocatalyst (Scheme 38) [72]. For the study of enantioselectivity of products, different N-substituted oxindoles with H, Me, phenyl, and benzyl groups were investigated. As the size of N-protecting
Acetaldehyde in the Enders triple cascade reaction via acetaldehyde dimethyl acetal
Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92
- proved to yield the desired product, indicating that the catalytic system may indeed be applicable. Lowering the amount of organocatalyst 1 to 10 mol % (Table 1, entry 2) resulted in a decrease of both yield and selectivity. Based on the results obtained (Table 1, entry 2) and the reaction conditions
Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update
Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72
- categorized into two major divisions: 1) covalent bonding and 2) noncovalent bonding catalysts. A covalent bonding organocatalyst reacts with a substrate to form an activated chiral intermediate which undergoes a stereoselective reaction with another reagent. A noncovalent bonding catalyst usually assembles
- -bonding interactions to facilitate a highly face-selective nucleophilic attack by π-nucleophile to the cyclic imine (see transition state 22’ in Scheme 7a). The BINOL-derived chiral phosphoric acid P8 was employed as the asymmetric organocatalyst for this transformation to construct the heterodimerized
Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach
Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71
- conditions by lowering the temperature from 170 °C to 120 °C. Varma and co-workers [80][81] reported the synthesis of various N-substituted pyrrole derivatives 57 in good yields using a nano-ferric-supported glutathione organocatalyst (Scheme 27, Figure 6). This organoccatalyst was prepared by a post
- -functionalization method using a benign and naturally occurring glutathione and magnetic ferrite nanoparticles by sonication in water at room temperature. Furthermore, using this organocatalyst, various N-substituted pyrroles were prepared by reacting various amines 56 with 2,5-DMTHF (2) in water at 140 °C under
- -substituted pyrroles catalyzed by nano-sulfated TiO2 catalyst. Nano-ferric supported glutathione organocatalyst. Various synthestic protocols for the synthesis of pyrroles. A general reaction of Clauson–Kaas pyrrole synthesis and proposed mechanism. AcOH-catalyzed synthesis of pyrroles 5 and 7. Synthesis of N
Computational studies of Brønsted acid-catalyzed transannular cycloadditions of cycloalkenone hydrazones
Beilstein J. Org. Chem. 2023, 19, 477–486, doi:10.3762/bjoc.19.37
- groups the global charge transfer is not so high to be considered a polar process. The reaction, as previously reported by the classical intermolecular reaction takes place smoothly by the action of the organocatalyst that renders a protonated hydrazone as the reacting functional group. However, in
Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview
Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35
- plausible mechanism. The amino acid acts as an organocatalyst and first reacts with the benzaldehyde 47 to generate the transient directing group (47’). Then, formation of the palladacycle (species R) followed by its oxidation to a Pd(IV) intermediate and a ligand exchange with 2,2,2-trifluoroethanol leads
- to the formation of the species S. The latter complex S undergoes a reductive elimination leading to the compound 48’ along with the regeneration of the palladium catalyst. Finally, after hydrolysis of 48’, the expected product 48 is afforded together with the organocatalyst. Then, the group of Sun
Identification and determination of the absolute configuration of amorph-4-en-10β-ol, a cadinol-type sesquiterpene from the scent glands of the African reed frog Hyperolius cinnamomeoventris
Beilstein J. Org. Chem. 2023, 19, 167–175, doi:10.3762/bjoc.19.16
- configuration. Controlling the stereogenic center C-4 of 4 would allow access to the respective enantiomers. Unfortunately, enantiomerically pure 4 is not easily available, in contrast to ketone 17. This compound can be obtained in high optical purity using Jørgensen’s organocatalyst 16 [20][21]. In addition
- , such a synthetic approach would shorten the synthesis from eight to four steps and allow access to both enantiomers of the compounds 12–14. The synthesis started with an enantioselective Michael addition of aldehyde 1 to methyl vinyl ketone (15) catalyzed by (S)-Jørgensen’s organocatalyst S-16, to
- organocatalyst S-16. Conditions: a) S-16 (5 mol %), ethyl 3,4-dihydroxybenzoate (0.2 equiv), 4 °C, 36 h; b) i) diethyl (2-methylallyl)phosphonate (1.5 equiv), THF, −78 °C, 10 min, ii) n-BuLi (1.5 equiv), THF, −78 °C, 1 h, iii) S-17 (1.0 equiv), −78 °C, 10 min, rt, 8 h; c) i) formaldehyde (0.4 equiv
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
- -organocatalyzed”. Within this section, two process types can be distinguished. In one an organocatalyst molecule is not reduced or oxidized itself but facilitates a reaction by activating the redox properties of reactants (Scheme 1, type II). In such processes the basic principles and organocatalyst structures
- organocatalyst does not undergo oxidation or reduction but facilitates interaction between oxidant and substrate (Scheme 1, type II organocatalysis) are fluently discussed below to show the fundamental difference between type II and type III redox-organocatalysis. Organocatalysis by activation of redox
- properties of reagents In this section we demonstrate examples of the main types of oxidative processes, in which an organocatalyst does not behave as a redox-active molecule itself but interacts with substrates and thus modulates their redox properties (Scheme 1, type II organocatalysis). Secondary amines
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