共查询到20条相似文献,搜索用时 15 毫秒
1.
Zhang X Zhang Y Huang J Hsung RP Kurtz KC Oppenheimer J Petersen ME Sagamanova IK Shen L Tracey MR 《The Journal of organic chemistry》2006,71(11):4170-4177
A general and efficient method for the coupling of a wide range of amides with alkynyl bromides is described here. This novel amidation reaction involves a catalytic protocol using copper(II) sulfate-pentahydrate and 1,10-phenanthroline to direct the sp-C-N bond formation, leading to a structurally diverse array of ynamides including macrocyclic ynamides via an intramolecular amidation. Given the surging interest in ynamide chemistry, this atom economical synthesis of ynamides should invoke further attention from the synthetic organic community. 相似文献
2.
Frederick MO Mulder JA Tracey MR Hsung RP Huang J Kurtz KC Shen L Douglas CJ 《Journal of the American Chemical Society》2003,125(9):2368-2369
A copper-catalyzed new C-N bond formation involving a sp-hybridized carbon is described here leading to a facile entry for syntheses of chiral ynamides. This direct N-alkynylation of amides should have a significant impact on the future development of synthetic methodologies employing ynamides. 相似文献
3.
An efficient and modular entry to α‐halogenated amides and esters is reported. This reaction is based on an underestimated double electrophilic activation of ynamides sequentially involving highly reactive activated keteniminium and iminium ions. Upon simple reaction with HCl and an electrophilic halogenation reagent in the presence of water or an alcohol, a broad range of ynamides can be transformed, in a highly divergent manner, to α‐halo amides and esters with high efficiency and under mild conditions. 相似文献
4.
[reaction: see text] A highly useful sequence of reactions is described here. These reactions consist of the first successful base-induced isomerizations of propargyl amides to chiral ynamides, applications of these novel ynamides in ring-closure metathesis leading to chiral 2-amidodienes useful for Diels-Alder cycloadditions, and the first successful tandem RCM of diene-ynamides. 相似文献
5.
Pierre Thilmany Prof. Gwilherm Evano 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(1):248-252
An efficient and modular entry to α-halogenated amides and esters is reported. This reaction is based on an underestimated double electrophilic activation of ynamides sequentially involving highly reactive activated keteniminium and iminium ions. Upon simple reaction with HCl and an electrophilic halogenation reagent in the presence of water or an alcohol, a broad range of ynamides can be transformed, in a highly divergent manner, to α-halo amides and esters with high efficiency and under mild conditions. 相似文献
6.
A copper-catalyzed method for the preparation of ynamides has been identified that proceeds via aerobic oxidative coupling of terminal alkynes with various nitrogen nucleophiles, including cyclic carbamates, amides and ureas, and N-alkyl-arylsulfonamides and indoles. 相似文献
7.
[reaction: see text] A general amination strategy for the N-alkynylation of carbamates, sulfonamides, and chiral oxazolidinones and imidazolidinones is described. A variety of substituted ynamides are available by deprotonation of amides with KHMDS followed by reaction with CuI and an alkynyl bromide. 相似文献
8.
Tim Wezeman Dr. Sabilla Zhong Dr. Martin Nieger Prof. Dr. Stefan Bräse 《Angewandte Chemie (International ed. in English)》2016,55(11):3823-3827
A diverse set of highly substituted 4‐aminoquinolines was synthesized from ynamides, triflic anhydride, 2‐chloropyridine, and readily accessible amides in a mild one‐step procedure. 相似文献
9.
Simple copper(II) hydroxide Cu(OH)(2) could act as an efficient heterogeneous catalyst for selective oxidative cross-coupling of a broad range of terminal alkynes and amides using air as a sole oxidant, giving the corresponding ynamides in moderate to high yields (56-93% yields). 相似文献
10.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(16):4636-4639
Multicomponent reactions are excellent tools for rapid generation of small molecules with broad chemical diversity and molecular complexity. Herein, a novel one‐pot multicomponent synthesis of β‐amino amides from aldehydes, anilines, carboxylic acids and ynamides has been successfully developed. This process is practical and efficient to unravel synthetic utility and scalability. Moreover, an isotope labeling reaction was conducted to elucidate a plausible reaction mechanism. 相似文献
11.
《中国化学快报》2021,32(8):2551-2554
Ynamides are electron-rich alkynes with unique reactivities and act as flexible building blocks in organic synthesis. Therefore, the investigation for transformation of ynamides with exceptional selectivity and efficiency is attractive and interesting. Herein, we report an oxoarylation of ynamides with N-aryl hydroxamic acids. In the presence of catalytic Cu(OTf)2, both the terminal and internal ynamides could undergo an addition/[3,3] sigmatropic rearrangement cascade with N-aryl hydroxamic acids to achieve oxoarylation, along with providing selective entry to (ortho-amino)arylacetamides and oxindoles. Moreover, deuterium-labelling reaction and gram-scale reaction were conducted to probe the mechanism and showcase the scalability. 相似文献
12.
A method for the catalytic hydrophosphinylation of internal ynamides with H-phosphinates has been developed for the first time. The protocol employing the catalyst generated from NiBr2 and PPh3 could be applied to several types of ynamides and H-phosphinates, affording (E)-β-aminovinylphosphinates in a highly regio- and stereoselective manner. 相似文献
13.
Dr. Rong Long Shaoling Huang Dr. Han-Kui Wu Naila Iqbal Dr. Na Wu 《European journal of organic chemistry》2023,26(32):e202300393
Ynamides/arylynamines are challenging substrates for oxyacetoxylation, especially due to various reactive sites of the N-heteroaryl ring. Herein, we report a metal-free PhI(OAc)2-mediated oxyacetoxylation of arylynamines/ynamides to provide α-acetoxyl amides in good to excellent yields. The transformation completes in a short time to afford solely the product in a highly regio- and chemo-selective manner through β-iodo keteneiminium intermediate, without functionalising the N-heteroaryl moiety. 相似文献
14.
《Angewandte Chemie (International ed. in English)》2017,56(8):2212-2215
A general, asymmetric redox arylation of ynamides and thioalkynes with chiral sulfoxides is reported. This is the first example of a general 1,4‐chirality transfer from sulfur to a carbon stereocenter through a sulfonium [3,3]‐sigmatropic rearrangement. This reaction delivers α‐arylated thioesters and amides under mild conditions in an atom‐economical manner. The products are formed in high yields with enantiomeric ratios up to 99.5:0.5. Quantum chemical calculations suggest a mechanism for the chirality transfer from sulfur to carbon and explain the experimentally observed correlation of the enantioselectivity with both the catalyst and the substrate. 相似文献
15.
Jonathan P. Markham Ban Wang Dr. Edwin D. Stevens Dr. Stuart C. Burris Dr. Yongming Deng 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(26):6638-6644
A photocatalyzed ortho-alkylation of pyridine N-oxide with ynamides and arylacetylenes has been developed, which yields a series of α-(2-pyridinyl) benzyl amides/ketones. Mechanistic studies, including electrochemical studies, radical-trapping experiments, and Stern–Volmer fluorescence quenching studies demonstrate that pyridine N-oxide serves as both a redox auxiliary and radical acceptor to achieve the mild photocatalytic single-electron oxidation of carbon–carbon triple bonds with the generation of a cationic vinyl radical intermediate. 相似文献
16.
Benoit Gourdet 《Tetrahedron》2010,66(32):6026-5103
In the presence of catalytic [Rh(cod)(MeCN)2]BF4, ynamides undergo carbometalation with boronic acids, arylboronic esters, and triarylboroxines. These reactions enable the regio- and stereocontrolled synthesis of multisubstituted enamides. 相似文献
17.
Highly Enantioselective Catalytic Asymmetric [2+2] Cycloadditions of Cyclic α‐Alkylidene β‐Oxo Imides with Ynamides
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Kazuaki Enomoto Harufumi Oyama Prof. Dr. Masahisa Nakada 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(7):2798-2802
Highly enantioselective catalytic asymmetric [2+2] cycloadditions of cyclic α‐alkylidene β‐oxo imides with ynamides are described. The high reactivity of the cyclic α‐alkylidene β‐oxo imide allows the [2+2] cycloadditions of a hindered substrate with unreactive ynamides at low temperature. The X‐ray crystallographic analysis of the product suggests that the enantioselectivity of the [2+2] cycloaddition can be well explained by the chelate model comprising the intramolecular hydrogen bond, wherein the cyclic α‐alkylidene β‐oxo imide coordinates with CuII through the two imide carbonyls. The imide group in the product can be transformed to amide, nitrile, and ester groups; moreover, it is removable. 相似文献
18.
Amides are generally considered as a low-reactive chemical entity among the carbonyl group, and therefore fewer opportunities to be involved in catalytic transformations as substrates. The origin of the stable nature of amides is resonance stabilization in the planar structure, which has drawn considerable attention from organic and physical chemists, leading to the discovery of distorted amides that exhibit a substantially reactive nature. Recent focus in this field is on the catalytic transformation of designed amides with moderate distortion or reduced resonance stabilization. This digest reviews the brief history of the quest for highly distorted amides and introduces a collection of recent studies on catalytic transformations of designed amides. 相似文献
19.
Al-Rashid ZF Johnson WL Hsung RP Wei Y Yao PY Liu R Zhao K 《The Journal of organic chemistry》2008,73(22):8780-8784
A de novo preparation of alpha-keto-imides via ynamide oxidation is described. With a number of alkyne oxidation conditions screened, a highly efficient RuO2-NaIO4 mediated oxidation and a DMDO oxidation have been identified to tolerate a wide range of ynamide types. In addition to accessing a wide variety of alpha-keto-imides, the RuO2-NaIO4 protocol provides a novel entry to the vicinal tricarbonyl motif via oxidation of push-pull ynamides, and imido acylsilanes from silyl-substituted ynamides. Chemoselective oxidation of ynamides containing olefins can be achieved by using DMDO, while the RuO2-NaIO4 protocol is not effective. These studies provide further support for the synthetic utility of ynamides. 相似文献
20.
Zinc(II)‐Catalyzed Intermolecular Hydrative Aldol Reactions of 2‐En‐1‐ynamides with Aldehydes and Water to form Branched Aldol Products Regio‐ and Stereoselectively
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Dr. Appaso Mahadev Jadhav Dr. Vinayak Vishnu Pagar Dr. Deepak B. Huple Prof. Dr. Rai‐Shung Liu 《Angewandte Chemie (International ed. in English)》2015,54(12):3812-3816
This work describes zinc(II)‐catalyzed hydrative aldol reactions of 2‐en‐1‐ynamides with aldehydes and water to afford branched aldol products regio‐ and stereoselectively. The anti and syn selectivity can be modulated by the sizes of sulfonamides to yield E‐ and Z‐configured zinc(II) dienolates selectively. This new reaction leads to enantiopure aldol products by using a cheap chiral sulfonamide. The mechanistic analysis reveals that the sulfonamide amides of the substrates can trap a released proton to generate dual acidic sites to activate a carbonyl allylation reaction. 相似文献