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1.
Indium Tribromide Catalyzed Coupling Reaction of Enol Ethers with Silyl Ketene Imines toward the Synthesis of β,γ‐Unsaturated Nitriles 下载免费PDF全文
Dr. Yoshihiro Nishimoto Takashi Nishimura Prof. Dr. Makoto Yasuda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(50):18301-18308
Herein, a coupling reaction of enol ethers with silyl ketene imines in the presence of catalytic amounts of InBr3 and Me3SiBr is described. Kinetic studies have revealed that an indium catalyst and Me3SiBr accelerated the coupling process and the regeneration of the catalyst, respectively. Various types of enol ethers and silyl ketene imines are applicable. In addition, a formal synthesis of verapamil was achieved by using this novel coupling reaction. 相似文献
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The pyrazolo[1,5‐a]pyrimidines 4, 10, 11 and 14 were synthesized from reaction of 4‐aryazo‐2,5‐diaminopyrazoles 1 with cyclic β‐ketoesters 2a,b or cyclic β‐ketoesters 7, 8 or acetoacetanilide 12 , respectively. The reaction of 1 with the enamines 15, 16 and 17 yielded also the pyrazolo[1,5‐a]pyrimidines 18, 20 and 21 , respectively. 相似文献
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Platinum‐Catalyzed Cascade Rearrangement Reaction of 1,5‐Diynyl Esters: Unusual Regioselective 1,5‐Hydride Migration 下载免费PDF全文
A highly regioselective sequential 1,3‐acyloxy migration/pentannulation/1,5‐hydride migration reaction is disclosed which provides an efficient access to (E)‐2‐vinyl‐3‐oxo‐1‐methyleneindenes under neutral and mild reaction conditions. The migrated hydrogen atom was derived from an unactivated alkyl group, and the long‐range 1,5‐H shift was confirmed through related deuterium experiments. 相似文献
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A series of novel racemic 2‐(1,3‐diaryl‐3‐hydroxypropyl)cyclohexan‐1‐ol derivatives were synthesized from 1,5‐diketones. All the synthesized compounds were characterized by spectroscopic methods. The antibacterial activities of obtained chiral 1,5‐diols were investigated against four Gram‐positive and three Gram‐negative bacteria by determining of minimum inhibitory concentrations (MICs) in vitro. Compounds 3b , 3c , and 3d were found to be active against Enterococcus faecalis and Escherichia coli. In addition, compound 3j were found to be moderately active against all tested bacterial strains. 相似文献
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A manganese‐catalyzed cross‐coupling reaction of thiols with aryl iodides, furnishing aryl thioethers in good to excellent yields has been reported; the system shows good functional group tolerance and enables the sterically demanding aryl iodides to couple with thiols. 相似文献
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Rebecca A. Green Prof. John F. Hartwig 《Angewandte Chemie (International ed. in English)》2015,54(12):3768-3772
The nickel‐catalyzed amination of aryl chlorides to form primary arylamines occurs with ammonia or ammonium sulfate and a well‐defined single‐component nickel(0) precatalyst containing a Josiphos ligand and an η2‐bound benzonitrile ligand. This system also catalyzes the coupling of aryl chlorides with gaseous amines in the form of their hydrochloride salts. 相似文献
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Majid M. Heravi Samaheh Sadjadi Hossein A. Oskooie Rahim Hekmatshoar Fatemeh F. Bamoharram 《中国化学会会志》2008,55(4):842-845
3H‐1,5‐benzodiazepines were synthesized by the condensation of o‐phenylendiamine and various 1,3‐diketones in the presence of various heteropolyacid (HPA) catalysts under mild conditions in very good yields and with high selectivity. 相似文献
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Facile Access to Fluoromethylated Arenes by Nickel‐Catalyzed Cross‐Coupling between Arylboronic Acids and Fluoromethyl Bromide 下载免费PDF全文
Lun An Yu‐Lan Xiao Qiao‐Qiao Min Prof. Dr. Xingang Zhang 《Angewandte Chemie (International ed. in English)》2015,54(31):9079-9083
The nickel‐catalyzed fluoromethylation of arylboronic acids was achieved with the industrial raw material fluoromethyl bromide (CH2FBr) as the coupling partner. The reaction proceeded under mild reaction conditions with high efficiency; it features the use of a low‐cost nickel catalyst, synthetic simplicity, and excellent functional‐group compatibility, and provides facile access to fluoromethylated biologically relevant molecules. Preliminary mechanistic studies showed that a single‐electron‐transfer (SET) pathway is involved in the catalytic cycle. 相似文献
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Asymmetric Hydrogenation of Vinylthioethers: Access to Optically Active 1,5‐Benzothiazepine Derivatives 下载免费PDF全文
Dr. Wei Li Christoph Schlepphorst Constantin Daniliuc Prof. Dr. Frank Glorius 《Angewandte Chemie (International ed. in English)》2016,55(10):3300-3303
A novel asymmetric hydrogenation of vinylthioethers was developed using a ruthenium(II) NHC complex. This method provides an efficient approach to optically active 1,5‐benzothiazepines featuring stereocenters with C?S bonds. Excellent enantioselectivities (up to 95 % ee) and high yields (up to 99 %) were obtained for a variety of substrates bearing a range of useful functional groups. Moreover, this methodology could be directly applied to the synthesis of the antidepressant drug R‐(?)‐thiazesim. 相似文献
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Dawei Ma Prof. Dr. Siwei Xie Peng Xue Xiaojing Zhang Prof. Dr. Jinhua Dong Yongwen Jiang Dr. 《Angewandte Chemie (International ed. in English)》2009,48(23):4222-4225
Don′t tell azole : The first metal‐catalyzed direct coupling of metal sulfides with aryl halides and subsequent intramolecular condensation provided substituted benzothiazoles (see scheme). A wide range of functional groups are tolerated under the reaction conditions.
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Copper‐Catalyzed One‐Pot Denitrogenative–Dehydrogenative–Decarboxylative Coupling of β‐Ketoacids with Trifluorodiazoethane: Facile Access to Trifluoromethylated Aldol Products 下载免费PDF全文
Dr. Heng‐Ying Xiong Zhen‐Yan Yang Zhen Chen Jun‐Liang Zeng Dr. Jing Nie Prof. Jun‐An Ma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(27):8325-8329
A novel copper‐catalyzed one‐pot cross‐coupling of β‐ketoacids with in situ generated trifluorodiazoethane has been developed. This reaction provides a direct and efficient method, in which one C?C bond and one C?O bond were formed in a carbenoid center with concomitant denitrogenation–dehydrogenation–decarboxylation, to afford trifluoromethylated aldol products. In several preliminary experiments, good to high enantioselectivities were also obtained. 相似文献
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Cyclization of 5‐cyano‐1,6‐dihydro‐4‐methyl‐2‐phenyl‐6‐thioxopyrimidine 4 with excess of 85% hydrazine hydrate afforded the 3‐amino‐4‐methyl‐6‐phenylpyrazolo[3,4‐d]pyrimidine 5 , which can react with appropriate Mannich base derivatives 13a‐c and chalcones 27a,b to yield the corresponding 6,8‐disubstituted 7,8‐dihydropyrimido[2,3:4,3]pyrazolo[1,5‐a]pyrimidines 15a‐c and 30a,b , respectively. On the other hand, the 6,7,8‐trisubstituted pyrimido[2,3:4,3]pyrazolo[1,5‐a]pyrimidine derivatives 8a‐g, 20a‐e, 36 and 38 were obtained by treatment of compound 5 with appropriate 1,3‐diketones 6a‐g , 3‐dimethylamino‐1‐(substituted)prop‐2‐enones 18a‐e , 3‐aminocrotononitrile 3 , and ethoxymethylenemalononitrile 37 under acidic condition, respectively. 相似文献
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Synthesis of 3,5‐Diarylcyclohex‐2‐enones by NH4Cl/HCl‐Catalyzed Cyclization and Deacetylation of 4‐Acetylhexane‐1,5‐diones 下载免费PDF全文
A new route for the synthesis of 3,5‐diarylcyclohex‐2‐enones is reported. The 4‐acetyl‐1,3‐diarylhexane‐1,5‐diones were obtained by the addition of pentane‐2,4‐dione to chalcones. The reaction of 4‐acetyl‐1,3‐diarylhexane‐1,5‐diones with NH4Cl/HCl in EtOH under reflux conditions gave the 3,5‐diarylcyclohex‐2‐enones in good yields. All synthesized compounds were characterized by spectroscopic methods (1H‐, 13C‐NMR, and IR), and elemental analyses. 相似文献
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Magda F. Fathalla 《中国化学》2012,30(1):109-114
Kinetics of the reaction of 2‐chloro‐3,5‐dinitrobenzotriflouride with aniline were studied in toluene, methanol‐toluene binary solvents, benzene and chloroform. The reaction in toluene exhibits third‐order kinetics consistent with aggregates of aniline. Thermodynamic parameters (H#, (S# and (G#are calculated and discussed for the reaction of 2‐chloro‐3,5‐dinitrobenzotriflouride with aniline in methanol‐toluene. Molecular complexes between aniline and the substrate are rejected spectrophotometricaly. The mechanism is studied and compared with the reaction in presence of pyridine. It shows an amine dependence and formation of homo and/or hetero mixed aggregates between aniline and pyridine i.e. dimer mechanism. 相似文献
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Transition‐Metal‐Catalyzed CH Bond Functionalizations: Feasible Access to a Diversity‐Oriented β‐Carboline Library 下载免费PDF全文
Ningjie Wu Dr. Feijie Song Lipeng Yan Juan Li Prof. Dr. Jingsong You 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(12):3408-3414
Diversification of the β‐carboline skeleton has been demonstrated to assemble a β‐carboline library starting from the tetrahydro‐β‐carboline framework. This strategy affords feasible access to heteroaryl‐, aryl‐, alkenyl‐, or alkynyl‐substituted β‐carbolines at the C1, C3, or C8 position through three categorically different types of transition‐metal‐catalyzed C?C bond‐forming reactions, in the presence of multiple potentially reactive positions. These site‐selective functionalizations include; 1) the Cu‐catalyzed C1/C3‐selective decarboxylative C?C and C?Csp coupling of hexahydro‐β‐carboline‐3‐carboxylic acid with a C?H bond of a heteroarene or terminal alkyne; 2) the chelation‐assisted Pd‐catalyzed C1/C8‐selective C?H arylation of hexahydro‐β‐carboline with aryl boron reagents; and 3) the chelation‐assisted Pd‐catalyzed C1/C3‐selective oxidative C?H/C?H cross‐coupling of β‐carboline‐N‐oxide with arenes, heteroarenes, or alkenes. The saturated structural feature of the hexahydro‐β‐carboline framework can increase reactivity and control site selectivity. The robustness of these approaches has been demonstrated through the synthesis of hyrtioerectine analogues and perlolyrine. We believe that these strategies could provide inspiration for late‐stage diversifications of bioactive core scaffolds. 相似文献
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Palladium‐Catalyzed Oxidative Difunctionalization of Alkenes with α‐Carbonyl Alkyl Bromides Initiated through a Heck‐type Insertion: A Route to Indolin‐2‐ones 下载免费PDF全文
Jian‐Hong Fan Wen‐Ting Wei Ming‐Bo Zhou Dr. Ren‐Jie Song Prof. Dr. Jin‐Heng Li 《Angewandte Chemie (International ed. in English)》2014,53(26):6650-6654
The oxidative interception of various σ‐alkyl palladium(II) intermediates with additional reagents for the difunctionalization of alkenes is an important research area. A new palladium‐catalyzed oxidative difunctionalization reaction of alkenes with α‐carbonyl alkyl bromides is described, in which the σ‐alkyl palladium(II) intermediate is generated through a Heck insertion and trapped using an aryl C(sp2)? H bond. This method can be applied to various α‐carbonyl alkyl bromides, including primary, secondary, and tertiary α‐bromoalkyl esters, ketones, and amides. 相似文献