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1.
Copper‐Catalyzed Reductive N‐Alkylation of Amides with N‐Tosylhydrazones Derived from Ketones 下载免费PDF全文
A CuI‐catalyzed reductive coupling of ketone‐derived N‐tosylhydrazones with amides is presented. Under the optimized conditions, an array of N‐tosylhydrazones derived from aryl–alkyl and diaryl ketones could couple effectively with a wide variety of (hetero)aryl as well as aliphatic amides to afford the N‐alkylated amides in high yields. The method represents the very few examples for reliably accessing secondary and tertiary amides through a reductive N‐alkylation protocol. 相似文献
2.
Redox Amination Scope of Benzylic Ketones with Indoline: Synthetic and Mechanistic Insights 下载免费PDF全文
Omer Aydin Haydar Kilic Sinan Bayindir Esra Erdogan Nurullah Saracoglu 《Journal of heterocyclic chemistry》2015,52(5):1540-1553
Bi(NO3)3·5H2O‐Catalyzed redox amination scope and mechanistic insights of benzylic ketones with indoline are discussed. The experimental results demonstrate that the formation of N‐alkyl‐substituted indole/indoline derivatives over typically competitive redox and reductive amination processes is depending upon the reaction condition for the benzylic ketones. 相似文献
3.
An N‐heterocyclic carbene/nickel‐catalyzed direct coupling of alcohols and internal alkynes to form α‐branched ketones has been developed. This methodology provides a new approach to afford branched ketones, which are difficult to access through the hydroacylation of simple internal alkenes with aldehydes. This redox‐neutral and redox‐economical coupling is free from any oxidative or reductive additives as well as stoichiometric byproducts. These reactions convert both benzylic and aliphatic alcohols and alkynes, two basic feedstock chemicals, into various α‐branched ketones in a single chemical step. 相似文献
4.
Facile One‐Pot Synthesis of N‐Alkylated Benzimidazole and Benzotriazole from Carbonyl Compounds 下载免费PDF全文
Xu Meng Xiaolong Li Wenlin Chen Yuanqing Zhang Wen Wang Jinying Chen Jinli Song Huijie Feng Baohua Feng 《Journal of heterocyclic chemistry》2014,51(2):349-356
An efficient one‐pot N‐alkylation of benzimidazole and benzotriazole from carbonyl compounds and tosylhydrazide has been accomplished via copper powder‐catalyzed N—H bond insertion affording N‐alkylated products in good yields. The reaction can tolerate a wide range of carbonyl compounds, such as aryl, alkyl, heterocyclic and α,β‐unsaturated ketones, and aldehydes. 相似文献
5.
Feiyang Xu Katerina M. Korch Donald A. Watson 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(38):13582-13585
For the first time, an aza‐Heck cyclization that allows the preparation of indoline scaffolds is described. Using N‐hydroxy anilines as electrophiles, which can be easily accessed from the corresponding nitroarenes, this method provides indolines bearing pendant functionality and complex ring topologies. Synthesis of challenging indolines, such as those bearing fully substituted carbon atoms at C2, is also possible using this method. 相似文献
6.
A Simple Synthesis of Polyfunctionalized 4‐Aminopyrazolidin‐3‐ones as ‘Aza‐deoxa’ Analogs of D‐Cycloserine 下载免费PDF全文
Ana Novak Matej Štefanič Uroš Grošelj Martina Hrast Marta Kasunič Stanislav Gobec Branko Stanovnik Jurij Svete 《Helvetica chimica acta》2014,97(2):245-267
A simple five‐step synthesis of fully substituted (4RS,5RS)‐4‐aminopyrazolidin‐3‐ones as analogs of D ‐cycloserine was developed. It comprises a two‐step preparation of 5‐substituted (4RS,5RS)‐4‐(benzyloxycarbonylamino)pyrazolidin‐3‐ones, reductive alkylation at N(1), alkylation of the amidic N(2) with alkyl halides, and simultaneous hydrogenolytic deprotection/reductive alkylation of the primary NH2 group. The synthesis enables an easy stepwise functionalization of the pyrazolidin‐3‐one core with only two types of common reagents, aldehydes (or ketones) and alkyl halides. The structures of products were elucidated by NMR spectroscopy and X‐ray diffraction. 相似文献
7.
Dr. Jihye Park Hyunjung Oh Saegun Kim Kyuneun Kim Dr. Ashok Kumar Pandey Sang Hoon Han Dr. Soo Bong Han Prof. Dr. In Su Kim 《Angewandte Chemie (International ed. in English)》2018,57(39):12737-12740
The ability to alkylate pyridines and quinolines is important for their further development as pharmaceuticals and agrochemicals, and for other purposes. Herein we describe the unprecedented reductive alkylation of pyridine and quinoline N‐oxides using Wittig reagents. A wide range of pyridine and quinoline N‐oxides were converted into C2‐alkylated pyridines and quinolines with excellent site selectivity and functional‐group compatibility. Sequential C?H functionalization reactions of pyridine and quinoline N‐oxides highlight the utility of the developed method. Detailed labeling experiments were performed to elucidate the mechanism of this process. 相似文献
8.
Cu‐Catalyzed Intramolecular Amidation of Unactivated C(sp3)−H Bonds To Synthesize N‐Substituted Indolines 下载免费PDF全文
Fei Pan Bin Wu Dr. Zhang‐Jie Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(19):6487-6490
A copper‐catalyzed intramolecular amidation of unactivated C(sp3)?H bonds to construct indoline derivatives has been developed. Such an amidation proceeded well at primary C?H bonds preferred to secondary C?H bonds. The transformation owned a broad substrate scope. The corresponding indolines were obtained in good to excellent yields. N‐Formal and other carbonyl groups were suitable and were easily deprotected and transformed into methyl or long‐chained alkyl groups. Preliminary mechanistic studies suggested a radical pathway. 相似文献
9.
Deqiang Liang Bojie Huo Yongrui Dong Yan Wang Ying Dong Baoling Wang Yinhai Ma 《化学:亚洲杂志》2019,14(11):1932-1936
A rare example of C(sp3)?H functionalization of simple alkanes with unactivated alkenes is presented. In the presence of a copper salt and di‐tert‐butyl peroxide (DTBP), N‐allyl anilines underwent exo‐selective alkylation/cyclization cascade with unactivated alkenic bonds as radical acceptors and simple alkanes as radical precursors, providing a direct access to 3‐alkyl indolines. The present protocol features simple operation, broad substrate scope and great exo selectivity. 相似文献
10.
Julius R. Reyes Prof. Dr. Viresh H. Rawal 《Angewandte Chemie (International ed. in English)》2016,55(9):3077-3080
A method is presented for the direct transformation of a ketone to the corresponding reduced alkyl chloride or bromide. The process involves the reaction of a ketone trityl hydrazone with tBuOCl to give a diazene which readily collapses to the α‐chlorocarbinyl radical, reduction of which by a hydrogen atom source gives the alkyl chloride product. The use of N‐bromosuccinimide provides the corresponding alkyl bromide. This unique transformation provides a reductive halogenation that complements Barton's redox‐neutral vinyl halide synthesis. 相似文献
11.
Dr. Vijay N. Wakchaure Philip S. J. Kaib Markus Leutzsch Prof. Dr. Benjamin List 《Angewandte Chemie (International ed. in English)》2015,54(40):11852-11856
A chiral disulfonimide (DSI)‐catalyzed asymmetric reduction of N‐alkyl imines with Hantzsch esters as a hydrogen source in the presence of Boc2O has been developed. The reaction delivers Boc‐protected N‐alkyl amines with excellent yields and enantioselectivity. The method tolerates a large variety of alkyl amines, thus illustrating potential for a general reductive cross‐coupling of ketones with diverse amines, and it was applied in the synthesis of the pharmaceuticals (S)‐Rivastigmine, NPS R‐568 Hydrochloride, and (R)‐Fendiline. 相似文献
12.
A series of piano‐stool Ru (II) complexes ( Ru 1–7 ) bearing ethylenediamine with aryl and aliphatic groups were prepared and fully characterized by 1H, 13C, 19F and 31P NMR spectroscopy, FT‐IR and elemental analysis. The crystal structures of Ru 2–4 and Ru 7 were determined by X‐ray crystallography. They were successfully applied to the alpha(α)‐alkylation of aliphatic and aromatic ketones with alcohols via the borrowing hydrogen strategy in mild reaction conditions within a short time. The catalytic system has a broad substrate scope, which allows the synthesis of alpha alkylated ketones with excellent yields. The electronic and steric effects of complexes on catalytic activity were analysed. The influence of the carbon chain length of the ligand on the alpha‐alkylation reaction of ketones was also investigated. The catalytic cycle was also examined by 1H‐NMR spectroscopy in d8‐toluene. 相似文献
13.
Yasser M. Loksha Erik B. Pedersen Ahmed A. El‐Barbary Mahmoud A. El‐Badawi Claus Nielsen 《Journal of heterocyclic chemistry》2003,40(4):593-599
4‐tert‐Butyl‐1,3‐dihydroimidazol‐2‐ones and 1,3‐dihydroimidazol‐2‐thiones were synthesized from 1‐amino‐3,3‐dimethylbutanone and subjected to alkylation reactions. The latter compounds were S‐alkyl‐ated with iodoacetamide under alkaline conditions. The N1 N3‐unsubstituted derivative was iodinated and subsequently alkylated with alkylation reagents which previously have been used for the synthesis of anti‐HTV active imidazoles. Unfortunately, the present products were devoid of activity against HTV. 相似文献
14.
Rui Guo Minghui Zuo Qinye Tian Chuanfu Hou Shouneng Sun Weihao Guo Hongfeng Wu Wenyi Chu Zhizhong Sun 《化学:亚洲杂志》2020,15(13):1976-1981
A visible light‐induced decarboxylative alkylation of heterocyclic aromatics with aliphatic carboxylic acids was developed by using anthocyanins as a photocatalyst under mild conditions. A series of alkylated heterocyclic compounds were obtained in moderate to good yields by using the metal‐free decarboxylative coupling reaction under blue light. This strategy uses cheap and readily available carboxylic acids as alkylation reagents with good functional group tolerance and environmental friendliness. It is worth noting that this is the first time that anthocyanin has been used to catalyze the Minisci‐type C?H alkylation. The mechanism of decarboxylation alkylation was studied by capturing the adduct of alkyl radical and hydroquinone, thus confirming a radical mechanism. This protocol provides an alternative visible light‐induced decarboxylative alkylation for the functionalization of heterocyclic aromatics. 相似文献
15.
Yuan‐Zheng Cheng Qing‐Ru Zhao Xiao Zhang Shu‐Li You 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(50):18237-18242
Dearomatization of indoles provides efficient synthetic routes for substituted indolines. In most cases, indoles serve as nucleophiles. Reported here is an asymmetric dearomatization reaction of indole derivatives that function as electrophiles. The combination of a photocatalyst and chiral phosphoric acid open to air unlocks the umpolung reactivity of indoles, enabling their dearomatization with N‐hydroxycarbamates as nucleophiles. A variety of fused indolines bearing intriguing oxy‐amines were constructed in excellent yields with moderate to high enantioselectivities. Mechanistic studies show that the realization of two sequential single‐electron transfer oxidations of the indole derivatives is key, generating the configurationally biased carbocation species while providing the source of stereochemical induction. These results not only provide an efficient synthesis of enantioenriched indoline derivatives, but also offer a novel strategy for further designing asymmetric dearomatization reactions. 相似文献
16.
Sofiya A. Runikhina Dr. Oleg I. Afanasyev Klim Biriukov Prof. Dr. Dmitry S. Perekalin Dr. Martin Klussmann Dr. Denis Chusov 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(71):16225-16229
Common and non-toxic aldehydes are proposed as reagents for alkylation of ketones instead of carcinogenic alkyl halides. The developed reductive alkylation reaction proceeds in the presence of the commercially available ruthenium catalyst [(cymene)RuCl2]2 (as low as 250 ppm) and carbon monoxide as the reducing agent. The reaction works well for a broad substrate scope, including aromatic and aliphatic aldehydes and ketones. It can be carried out without a solvent and often gives nearly quantitative yields of the products. This straightforward and cost-effective method is promising not only for laboratory application but also for industry, which produces carbon monoxide as a large-scale waste product. 相似文献
17.
Davide Spinnato Bertrand Schweitzer‐Chaput Giulio Goti Maksim Oeka Paolo Melchiorre 《Angewandte Chemie (International ed. in English)》2020,59(24):9485-9490
Reported herein is a visible‐light‐mediated radical approach to the α‐alkylation of ketones. This method exploits the ability of a nucleophilic organocatalyst to generate radicals upon SN2‐based activation of alkyl halides and blue light irradiation. The resulting open‐shell intermediates are then intercepted by weakly nucleophilic silyl enol ethers, which would be unable to directly attack the alkyl halides through a traditional two‐electron path. The mild reaction conditions allowed functionalization of the α position of ketones with functional groups that are not compatible with classical anionic strategies. In addition, the redox‐neutral nature of this process makes it compatible with a cinchona‐based primary amine catalyst, which was used to develop a rare example of enantioselective organocatalytic radical α‐alkylation of ketones. 相似文献
18.
A series of new N‐substituted iminosugars were successfully synthesized through a general synthetic route from D‐xylose derivative. This approach provided a convenient access to the synthesis of N‐alkylated iminosugars as potential glucosidase inhibitors, which included a reaction of reductive amination. Various N‐alkylated iminosugars were prepared in good yields with high stereoselectivity. 相似文献
19.
Chiral Phosphoric Acid Catalyzed Kinetic Resolution of Indolines Based on a Self‐Redox Reaction 下载免费PDF全文
Dr. Kodai Saito Prof. Dr. Takahiko Akiyama 《Angewandte Chemie (International ed. in English)》2016,55(9):3148-3152
A strategy for oxidative kinetic resolution of racemic indolines was developed, employing salicylaldehyde derivative as the pre‐resolving reagent and chiral phosphoric acid as the catalyst. The iminium intermediate, formed by the condensation reaction of an enantiomer of indoline with salicylaldehyde derivative, was hydrogenated by the same enantiomer of indoline to afford another enantiomer of indoline by a self‐redox mechanism. The oxidative kinetic resolution of 2‐aryl‐substituted indolines proceeded to give enantiomers in good yields with excellent enantioselectivities. 相似文献
20.
Ming‐Zhong Wang Cong‐Ying Zhou Man‐Kin Wong Dr. Chi‐Ming Che Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(19):5723-5735
Ruthenium porphyrins (particularly [Ru(2,6‐Cl2tpp)CO]; tpp=tetraphenylporphinato) and RuCl3 can act as oxidation and/or Lewis acid catalysts for direct C‐3 alkylation of indoles, giving the desired products in high yields (up to 82 % based on 60–95 % substrate conversions). These ruthenium compounds catalyze oxidative coupling reactions of a wide variety of anilines and indoles bearing electron‐withdrawing or electron‐donating substituents with high regioselectivity when using tBuOOH as an oxidant, resulting in the alkylation of N‐arylindoles to 3‐{[(N‐aryl‐N‐alkyl)amino]methyl}indoles (yield: up to 82 %, conversion: up to 95 %) and the alkylation of N‐alkyl or N‐H indoles to 3‐[p‐(dialkylamino)benzyl]indoles (yield: up to 73 %, conversion: up to 92 %). A tentative reaction mechanism involving two pathways is proposed: an iminium ion intermediate may be generated by oxidation of an sp3 C? H bond of the alkylated aniline by an oxoruthenium species; this iminium ion could then either be trapped by an N‐arylindole (pathway A) or converted to formaldehyde, allowing a subsequent three‐component coupling reaction of the in situ generated formaldehyde with an N‐alkylindole and an aniline in the presence of a Lewis acid catalyst (pathway B). The results of deuterium‐labeling experiments are consistent with the alkylation of N‐alkylindoles via pathway B. The relative reaction rates of [Ru(2,6‐Cl2tpp)CO]‐catalyzed oxidative coupling reactions of 4‐X‐substituted N,N‐dimethylanilines with N‐phenylindole (using tBuOOH as oxidant), determined through competition experiments, correlate linearly with the substituent constants σ (R2=0.989), giving a ρ value of ?1.09. This ρ value and the magnitudes of the intra‐ and intermolecular deuterium isotope effects (kH/kD) suggest that electron transfer most likely occurs during the initial stage of the oxidation of 4‐X‐substituted N,N‐dimethylanilines. Ruthenium‐catalyzed three‐component reaction of N‐alkyl/N‐H indoles, paraformaldehyde, and anilines gave 3‐[p‐(dialkylamino)benzyl]indoles in up to 82 % yield (conversion: up to 95 %). 相似文献