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1.
Enantioenriched substituted succinimides are interesting compounds, and their asymmetric organocatalytic synthesis by the conjugated addition of ketones to maleimides has been scarcely explored. This study shows the enantioselective conjugate addition of ketones to maleimides organocatalyzed by a simple primary amine-salicylamide derived from a chiral trans-cyclohexane-1,2-diamine, which provides the desired succinimides in good to excellent yields (up to 98%) and with moderate to excellent enantioselectivities (up to 99%). 相似文献
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《Physics and Chemistry of Liquids》2012,50(2):193-201
Abstract The catalytic effect of lithium perchlorate on ene reaction of cis-cyclooctene with diethyl azodicarboxylate, 4-phenyl-1,2,4-triazoline-3,5-dione and the metallo-ene reaction of diallyldibutyltin with diethyl azodicarboxylate has been studied in different solvents like acetonitrile, acetone, diethyl ether, dimethylformamide and ethyl acetate. 相似文献
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Mohammad M. Mojtahedi Hassan Abassi M. Saeed Abaee Bahareh Mohebali 《Monatshefte für Chemie / Chemical Monthly》2006,137(4):455-458
Summary. Solvent-free ring opening of 1,2-epoxides with thiols using catalytic amounts of lithium perchlorate affords high yields of
β-hydroxy sulfides. Nucleophilic attack of the thiols occurs regioselectively at the sterically less hindered side of the
epoxides. 相似文献
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Several aminovinyl phosphonates were prepared in good yield by four-component aminoalkylation of aldehydes with diethyl(trimethylsilyl)amine, triethylphosphite and dimethyl acetylenedicarboxylate mediated by a 5 molar solution of lithium perchlorate in diethyl ether. 相似文献
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Recent progress in asymmetric organocatalysis has led to the development of several asymmetric transformations that employ various substrates. Among these substrates, maleimides have emerged as excellent Michael acceptors, dienophiles, and dipolarophiles. In this Focus Review we highlight the advances in the asymmetric synthesis of succinimide derivatives through asymmetric organocatalytic addition reactions of maleimides. 相似文献
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Direct Synthesis of Chiral 3‐Arylsuccinimides by Rhodium‐Catalyzed Enantioselective Conjugate Addition of Arylboronic Acids to Maleimides
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Dr. Balraj Gopula Shu‐Han Yang Ting‐Shen Kuo Prof. Dr. Jen‐Chieh Hsieh Dr. Ping‐Yu Wu Dr. Julian P. Henschke Prof. Dr. Hsyueh‐Liang Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):11050-11055
Chiral rhodium catalysts comprising 2,5‐diaryl‐ substituted bicyclo[2.2.1]diene ligands L1 – L10 were utilized in the enantioselective 1,4‐addition reaction of arylboronic acids to N‐substituted maleimides. In the presence of 2.5 mol % of RhI/ L2 , enantioenriched conjugate addition adducts were isolated in 72–99 % yields with 86–98 % ee. This protocol offers a convenient method to access a variety of 3‐arylsuccinimides in a highly enantioselective manner. Maleimides with readily cleavable N‐protecting groups were tolerated enabling the synthesis of useful synthetic intermediates. Pyrrolidine 4 , a biologically active compound, and pyrrolidine 5 , an ent‐precursor to an HSD‐1 inhibitor, were synthesized to demonstrate the utility of this method. 相似文献
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高氯酸锂促进的固体酸催化酯化反应 总被引:3,自引:0,他引:3
将二(三氟甲基磺酰)亚胺镱(Ⅲ)[Yb(NTf2)3]负载于NKC-9树脂上得到一种催化活性更高的酯化固体酸催化剂,发现高氯酸锂能够显著加速固体酸催化剂酯化反应速度,在不分水,相对于苯甲酸负载树脂用量30 wt%,Yb(NTf2)3用量0.8mol%,LiClO4用量58 mol%,n(苯甲酸):n(乙醇)=1:7的条件下,2 h内即可使苯甲酸与乙醇的直接酯化反应进行完全.同时研究了负载量、温度、高氯酸锂用量对苯甲酸酯化反应的影响. 相似文献
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A. Yıldırım 《合成通讯》2014,44(8):1137-1141
The cationic-type surfactant-catalyzed conjugate addition reaction of long-alkyl-chained thiols with N-aryl-substituted maleimides in water as a green reaction medium afforded the corresponding thia-Michael adducts in moderate to good yields.
[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] 相似文献
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Dr. Marzia Dell'Aera Dr. Filippo Maria Perna Dr. Paola Vitale Dr. Angela Altomare Prof. Alessandro Palmieri Dr. Lewis C. H. Maddock Leonie J. Bole Dr. Alan R. Kennedy Prof. Eva Hevia Prof. Vito Capriati 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(40):8742-8748
We report the first transition metal catalyst- and ligand-free conjugate addition of lithium tetraorganozincates (R4ZnLi2) to nitroolefins. Displaying enhanced nucleophilicity combined with unique chemoselectivity and functional group tolerance, homoleptic aliphatic and aromatic R4ZnLi2 provide access to valuable nitroalkanes in up to 98 % yield under mild conditions (0 °C) and short reaction time (30 min). This is particularly remarkable when employing β-nitroacrylates and β-nitroenones, where despite the presence of other electrophilic groups, selective 1,4 addition to the C=C is preferred. Structural and spectroscopic studies confirmed the formation of tetraorganozincate species in solution, the nature of which has been a long debated issue, and allowed to unveil the key role played by donor additives on the aggregation and structure of these reagents. Thus, while chelating N,N,N’,N’-tetramethylethylenediamine (TMEDA) and (R,R)-N,N,N’,N’-tetramethyl-1,2-diaminocyclohexane (TMCDA) favour the formation of contacted-ion pair zincates, macrocyclic Lewis donor 12-crown-4 triggers an immediate disproportionation process of Et4ZnLi2 into equimolar amounts of solvent-separated Et3ZnLi and EtLi. 相似文献
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M. Saeed Abaee Mohammad M. Mojtahedi M. Mehdi Zahedi S. Mohammad Bolourtchian 《合成通讯》2013,43(2):199-206
A remarkably efficient double‐crossed aldol condensation of tetrahydropyran‐4‐one with a variety of aromatic aldehydes is described at room temperature in the presence of (trimethylsilyl)diethylamine and lithium perchlorate under solvent‐free conditions. Excellent yields of 3,5‐bis(arylmethylidene)pyranones are achieved in a facile one‐pot general procedure. 相似文献
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Greta Vastakaite Dr. Claudio E. Grünenfelder Prof. Helma Wennemers 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(18):e202200215
Catalytic stereoselective additions with maleimides are useful one-step reactions to yield chiral succinimides, molecules that are widespread among therapeutically active compounds but challenging to prepare when the maleimide is C-substituted. We present the tripeptide H-Pro-Pro-Asp-NHC12H25 as a catalyst for conjugate addition reactions between aldehydes and C-substituted maleimides to form succinimides with three contiguous stereogenic centers in high yields and stereoselectivities. The peptidic catalyst is so chemoselective that no protecting group is needed at the imide nitrogen of the maleimides. Derivatization of the succinimides was straightforward and provided access to chiral pyrrolidines, lactones, and lactams. Kinetic studies, including a Hammett plot, provided detailed insight into the reaction mechanism. 相似文献
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Solvation interaction and ion association in solutions of lithium perchlorate/4-methoxymethyl-ethylene carbonate (MEC) have been studied by using Infrared and Raman spectra as a function of concentration of lithium perchlorate. The splitting of ring deformation band and ring ether asymmetric stretching band, and the change of carbonyl stretching band suggest that there should be a strong interaction between Li^+ and the solvent molecules, and the site of solvation should be the oxygen atom of carbonyl group. The apparent solvation number of Li^+ was calculated by using band fitting technique. The solvation number was decreased from 3.3 to 1.1 with increasing the concentration of LiClO4/MEC solutions. On the other hand, the band fitting for the ClO4^- band revealed the presence of contact ion pair, and free ClO4^- anion in the concentrated solutions. 相似文献
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Regioselective reaction of a lithium organocuprate (R2CuLi) and a polyconjugated carbonyl compound affords a remote‐conjugate‐addition product. This reaction proceeds particularly cleanly when the conjugation is terminated by a C? C triple bond. The reaction pathways and the origin of the regioselectivity of this class of transformations are explored with the aid of density functional calculations. The outline of the reaction pathway is as follows. An initially formed β‐cuprio(III) enolate intermediate undergoes smooth copper migration along the conjugated system. This process takes place faster than reductive elimination of intermediary σ/π‐allylcopper(III) species, since the latter reaction disrupts the conjugation in the substrate and hence is not preferred. The copper migration to the acetylenic terminal affords a σ/π‐allenylcopper(III) intermediate, which undergoes facile and selective C? C bond forming reductive elimination at the terminal carbon atom. The present mechanistic framework shows good agreement with some pertinent experimental data, including 13C NMR chemical shifts and kinetic isotope effects. 相似文献
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Enantioselective Organocatalyzed Michael Addition of Isobutyraldehyde to Maleimides in Aqueous Media
Thiourea was introduced into (R,R)-1,2-diphenylethylenediamine as an organocatalyst to promote the reaction between isobutyraldehydes and maleimides. Enantioselective Michael addition reaction was carried out as an eco-friendly method using water as the solvent. As a result of the reaction between isobutyraldehyde and maleimide, ≥97% yield and 99% enantioselectivity were obtained at a low catalyst loading of 0.01 mol%. The solvent effect can be explained by theoretical calculations that indicate the participation of a transition state, in which the CF3 substituent of the catalyst is a hydrogen bond activated by the surrounding water molecules. This discovery enabled the use of low catalyst loading in the organic reactions of chiral substances for pharmaceutical applications. Furthermore, a solvent effect for Michael reaction of the organocatalysts was proposed, and the organic reaction mechanisms were determined through quantum calculations. 相似文献
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Back Cover: Direct Synthesis of Chiral 3‐Arylsuccinimides by Rhodium‐Catalyzed Enantioselective Conjugate Addition of Arylboronic Acids to Maleimides (Chem. Eur. J. 31/2015)
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Dr. Balraj Gopula Shu‐Han Yang Ting‐Shen Kuo Prof. Dr. Jen‐Chieh Hsieh Dr. Ping‐Yu Wu Dr. Julian P. Henschke Prof. Dr. Hsyueh‐Liang Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):11256-11256