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1.
Ming Gong Prof. Dr. Jing‐Mei Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(40):14293-14296
A mild method for the direct C?H/N?H coupling between γ‐lactams and anilines through electrochemical oxidation has been developed. The protocol proceeded smoothly without metal catalysts at room temperature to afford γ‐substituted γ‐lactams in good yields. It has been revealed that the quasi‐divided cell which provided high current density on the anode was crucial for this reaction. 相似文献
2.
Eric L. Williams 《Journal of heterocyclic chemistry》1992,29(7):1735-1739
Treatment of large-ring lactams 1 with potassium t-butoxide results in the formation of bicyclic structures 2 . Evidence was obtained to support the formation of 2 through a carbene-anion coupling. The structures of a series of bicyclic lactams 2 have been rigorously defined. 相似文献
3.
R. G. Andrew R. E. Conrow J. D. Elliott W. S. Johnson S. Ramezani 《Tetrahedron letters》1987,28(52):6535-6538
Several (3S,4S)- and (3S,4R)-statine derivatives have been prepared by attack of nucleophiles on crystalline, epimeric N-BOC-lactams 7a and 7b. The key step in the synthesis of the lactams was the TiCl4-catalyzed coupling reactions of acetals derived from (R)-1,3-butanediol with allyltrimethylsilane.
Several enantiometrically pure (3S,4S- and (3S, 4R)-statine derivatives were made by sodium cyanide-catalyzed reaction of nucleophiles with the lactams 3a and 3b which were synthesized by the scheme 1 → 2 → 3. 相似文献
4.
A novel extension of Meyer's lactamization is reported for the preparation of seven-membered ring lactams 1a-d incorporating a biaryl unit. The required keto-esters 2a-c were readily accessible via the Suzuki coupling reaction. A borylation-Suzuki coupling (BSC) sequence was successfully developed for the high-yielding preparation of keto-ester 2d. Cyclization of the resulting keto-esters 2a-d or keto-acids 5a,c,d in the presence of (R)-phenylglycinol afforded the desired lactams 1a-d in high yields (72-93%) and excellent diastereoselectivities (>95%). This methodology provides a facile stereoselective access to new axially chiral bridged biaryls. 相似文献
5.
Naoki Kise Yosei Takenaga Yohei Ishikawa Yoichi Morikami Toshihiko Sakurai 《Tetrahedron letters》2012,53(15):1940-1945
The reductive coupling of N-methoxycarbonyl lactams with benzophenone by Zn-TiCl4 in THF gave cross-coupled products as cyclic α-diphenylidene-N-methoxycarbonylamines and ring-opening α,α-diphenyl-α-hydroxy-ω-(N-methoxycarbonyl)amino ketones selectively depending on the reduction conditions. The reductive coupling of N-methoxycarbonyl lactams with 9-fluorenone by Zn-TiCl4 gave cyclic α-(9H-fluoren-9-ylidene)-N-methoxycarbonylamines preferentially irrespective to the conditions. 相似文献
6.
[structure: see text]. In studies directed toward gymnodimine and related marine toxins, a single-pot variation of the Hua cyclic imine synthesis has been developed. The reaction involves generation of N-trimethylsilyl lactams in situ followed by alkyllithium addition leading directly to cyclic imines. Importantly, this reaction proceeds efficiently with highly hindered alpha,alpha-dialkyl lactams, provided 1,2-dimethoxyethane (DME) is used as solvent, leading to stable cyclic imines. Overall, this transformation allows a one-pot coupling of an alkyliodide and a lactam to give a cyclic imine. 相似文献
7.
A direct one-pot synthesis of phenanthrene lactams, which employs a Suzuki-Miyaura coupling/aldol condensation cascade reaction of isoindolin-1-one with 2-formylphenylboronic acid, has been developed. The approach is used to efficiently produce a number of natural aristolactams, such as aristolactam BII (cepharanone B), aristolactam BIII, aristolactam FI (piperolactam A), N-methyl piperolactam A, and sauristolactam. 相似文献
8.
Application of the palladium-catalyzed borylation/Suzuki coupling (BSC) reaction to the synthesis of biologically active biaryl lactams 总被引:2,自引:0,他引:2
The palladium-catalyzed, two-step, one-pot borylation/Suzuki coupling (BSC) reaction was developed to synthesize sterically hindered 2,2'-disubstituted biphenyl and phenyl-indole compounds in a short, simple, and efficient manner from two easily accessible aryl halides. High yields can be obtained by choosing properly both components according to their rough electronic properties. The illustration of the utility of this method was provided by the solution and solid-phase synthesis of seven- or eight-membered biphenyl lactams 5a-e, as well as paullone 3a. These compounds exhibit moderate albeit significant cytotoxicities and may serve as structural models for future medicinal chemistry developments. 相似文献
9.
[structures: see text] A systematic study was performed to establish general synthesis protocols for forming enantiomerically pure macrocyclic dipeptide lactams. Focusing on macrocycles of 8-, 9-, and 10-membered rings, effective syntheses were achieved by a sequence featuring peptide coupling of allyl- and homoallyl-glycine building blocks followed by ring-closing metathesis. The 8-membered lactam-possessing cis-amide and cis-olefin geometry as well as 9-membered [corrected] lactams having trans-amide and cis-olefin [corrected] configurations were effectively prepared by a general strategy employing the respective protected dipeptide, the first generation Grubbs' catalyst, and temporary protection of the central amide as a benzyl derivative. The 10-membered macrocycle was synthesized possessing cis- or trans-olefin geometry by employing similar metathesis conditions in the presence or absence of temporary benzyl amide protection, respectively [corrected] 相似文献
10.
With the catalysis of CuI/N,N'-dimethylethylenediamine, intramolecular C-N coupling between sulfonamides and vinyl halides was successfully implemented, leading to the efficient synthesis of 5-, 6-, 7-, and even 8-membered heterocyclic enamines in both exo and endo modes. The bicyclic enamines thus formed provided a convenient entry to the corresponding 9- to 12-membered lactams by oxidative C=C bond cleavage. 相似文献
11.
M. Lakshmi Kantam Chandrakanth Gadipelly Gunjan Deshmukh K. Rajender Reddy Suresh Bhargava 《Chemical record (New York, N.Y.)》2019,19(7):1302-1318
Activation of C?H bonds and their application in cross coupling chemistry has received a wider interest in recent years. The conventional strategy in cross coupling reaction involves the pre‐functionalization step of coupling reactants such as organic halides, pseudo‐halides and organometallic reagents. The C?H activation facilitates a simple and straight forward approach devoid of pre‐functionalization step. This approach also addresses the environmental and economical issues involved in several chemical reactions. In this account, we have reported C?H bond activation of small organic molecules, for example, formamide C?H bond can be activated and coupled with β‐dicarbonyl or 2‐carbonyl substituted phenols under oxidative conditions to yield carbamates using inexpensive copper catalysts. Phenyl carbamates were successfully synthesized in moderate to good yields by cross dehydrogenative coupling (CDC) of phenols with formamides using copper catalysts in presence of a ligand. We have also prepared unsymmetrical urea derivatives by oxidative cross coupling of formamides with amines using copper catalysts. Synthesis of N,N‐dimethyl substituted amides, 5‐substituted‐γ‐lactams and α‐acyloxy ethers was carried out from carboxylic acids using recyclable CuO nanoparticles. Copper nanoparticles afforded N‐aryl‐γ‐amino‐γ‐lactams by oxidative coupling of aromatic amines with 2‐pyrrolidinone. Reusable transition metal HT‐derived oxide catalyst was used for the synthesis of N,N‐dimethyl substituted amides by the oxidative cross‐coupling of carboxylic acids and substituted benzaldehydes. Overview of our work in this area is summarized. 相似文献
12.
Soares do Rêgo Barros O Nogueira CW Stangherlin EC Menezes PH Zeni G 《The Journal of organic chemistry》2006,71(4):1552-1557
We present here carbon-nitrogen bond formation via a coupling reaction of 2-iodo-selenophene catalyzed by Cu(I) in the presence of a base and an inexpensive ligand, and establish the first route to obtaining 2-nitrogen-selenophene derivatives in good yields. We can anticipate that this reaction works well with oxazolidinones, lactams, and aliphatic and aromatic amides, as nitrogen sources, in the absence of any supplementary additives. In addition, the reaction proceeded cleanly under mild reaction conditions and was sensitive to the ratio of amide/2-iodo-selenophene, as well as the nature of the ligand, base, and solvent. 相似文献
13.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(44):14012-14016
Nickel‐catalyzed coupling of benzyl acrylates with activated ketones and imines provides γ‐butyrolactones and lactams, respectively. The benzyl alcohol byproduct released during the lactonization/lactamization event is relayed to the next cycle where it serves as the reductant for C−C bond formation. This strategy represents a conceptually unique approach to transfer‐hydrogenative C−C bond formation, thus providing examples of reductive heterocyclizations where hydrogen embedded within an alcohol leaving group facilitates turnover. 相似文献
14.
A palldium(0)-catalyzed tandem cyclization/Suzuki coupling reaction of various 1,6-enyne substrates was developed. This Pd-catalyzed enyne cyclization reaction represents a new process for the synthesis of stereodefined alpha-arylmethylene-gamma-butyrolactones, lactams, multifunctional tetrahydrofurans, pyrrolidines, and cyclopentanes. The mechanism of the reaction was studied by the employment of different enyne isomers and boronic acids; a pi-allyl palladium intermediate was suggested to explain the formation of the cyclic products. The stereochemistry of this reaction can be well explained by a chairlike transition state. 相似文献
15.
[reaction: see text] Cu(I)-catalyzed coupling of lactams with (E)-2-chlorovinyliodides or (E)-2-bromovinyliodides produces the corresponding beta-haloenamides in moderate to excellent yields. 相似文献
16.
Toward concise access to functionalized amides and lactams, palladium‐catalyzed amidations of alkynes and alkenes with formamide derivatives were developed. Cyanoformamides having an alkynyl group were found to undergo intermolecular cyanoamidation in the presence of palladium catalyst to afford α‐alkylidene lactams. Whereas, when cyanoformamides that possess a 1,1‐disubstituted alkenyl group were used as starting materials, α,α‐disubstituted lactams were obtained. The latter reaction was extended to enantioselective transformation by utilizing optically active phosphoramidites as ligand. Furthermore, chloroformamides having a 1,1,2‐trisubsituted alkenyl group were found to give α‐vinyl‐lactams in the presence of palladium catalyst, base and silver salt. Additionally, formal intermolecular hydroamidation of alkenes was performed through one‐pot hydroboration‐carbamoylation sequence. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 386–394; 2008: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20159 相似文献
17.
The Stille coupling reaction of 3-(benzyloxymethyl)-1-(tert-butyldiphenylsiloxy)ethyl-1-(tributylstannyl)allene with N-(tert-butoxycarbonyl)-2-iodoaniline directly produced the corresponding 2-vinylindole derivative, which was independently transformed into natural (-)-goniomitine and unnatural (+)-goniomitine via the cross-metathesis with chiral oxazolopiperidone lactams. The antiproliferative activity of the synthesized natural (-)-goniomitine in Mock and MDCK/MDR1 cells showed them to be more potent to retard cell growth than unnatural (+)-goniomitine. 相似文献
18.
Jamison B. Tuttle Joseph M. AzzarelliBruce M. Bechle Amy B. DounayEdelweiss Evrard Xinmin GanSomraj Ghosh Jaclyn HendersonJi-Young Kim Vinod D. ParikhPatrick R. Verhoest 《Tetrahedron letters》2011,52(41):5211-5213
We describe modified Negishi coupling conditions that allow improved access to ortho-nitrophenylalanine derivatives. These useful amino acid intermediates can be further elaborated into biologically active lactams and cyclic hydroxamic acid targets. 相似文献
19.
Dr. Qianjia Yuan Prof. Matthew S. Sigman 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(46):10823-10827
In this report, a palladium-catalyzed redox-relay Heck process to access optically active alkenylated α,β-unsaturated lactams is described. Under mild reaction conditions, electron-deficient alkenyl triflates and electron-rich alkenyl iodonium salts undergo enantioselective and site-selective coupling with enelactams to deliver the products in high yields and excellent enantioselectivities. Furthermore, the products allow facile access to natural products such as (+)-calvine and (+)-2-epicalvine in addition to the bioactive molecule aza-goniothalamin. 相似文献
20.
An economical, solvent-free, and metal-free method for peptide synthesis via C–N bond cleavage using lactams has been developed. The method not only eliminates the need for condensation agents and their auxiliaries, which are essential for conventional peptide synthesis, but also exhibits high atom economy. The reaction is versatile because it can tolerate side chains bearing a range of functional groups, affording up to >99% yields of the corresponding peptides without racemisation or polymerisation. Moreover, the developed strategy enables peptide segment coupling, providing access to a hexapeptide that occurs as a repeat sequence in spider silk proteins.An economical, solvent-free, and metal-free method for peptide synthesis via C–N bond cleavage using lactams has been developed. 相似文献