共查询到20条相似文献,搜索用时 62 毫秒
1.
Tomohiro Ueda 《Tetrahedron》2010,66(39):7726-5799
Enantioselective alkynylation of aldehydes and ketones was accomplished using trimethoxysilylalkynes as alkynylating reagents and lithium 3,3′-diphenylbinaphtholate as a catalyst. Optically active propargylic alcohols were obtained in good to high chemical yields and enantioselectivities. Alkynylation of acetylpyridines afforded biologically active pyridyl propargylic alcohols in good enantioselectivities. 相似文献
2.
《Tetrahedron: Asymmetry》2001,12(15):2147-2152
A series of binaphthyl-derived amino alcohols were synthesized and used as catalytic ligands in the asymmetric alkynylation of aromatic aldehydes in the presence of a dialkylzinc reagent. The alkynylation of a variety of aromatic aldehydes gave the corresponding chiral propargylic alcohols in 61–93% e.e. 相似文献
3.
A one-pot, enantioselective synthesis of N-aryl propargylic amines, using alkynylation reagents obtained from dimethylzinc and terminal acetylenes in combination with various aldehydes and o-methoxyaniline as starting materials, has been developed. Enantiopure beta-amino alcohols derived from norephedrine were used as non-covalent chiral auxiliaries, both in stoichiometric or substoichiometric amount. After optimization, propargylic amines were obtained in good to high yields (up to 93%) and with moderate to high enantiomeric excesses (up to 97% ee). The possibility to recover the chiral auxiliary after the reaction was demonstrated. 相似文献
4.
Antonio L. Braga Helmoz R. Appelt Claudio C. Silveira Ludger A. Wessjohann Paulo H. Schneider 《Tetrahedron》2002,58(52):10413-10416
The enantioselective alkynylation reaction of aldehydes with alkynes and diethylzinc, catalyzed by chiral disulfide–oxazolidine ligands, provides a simple, practical and inexpensive method to access chiral propargylic alcohols in good yields and satisfactory ee's. 相似文献
5.
A new inexpensive chiral amino alcohol-based ligand, (1S,2S)-2-N,N-dimethylamino-1-(p-nitrophenyl)-3- (t-butyldimethylsilyloxy)propane-1-ol, was developed for the asymmetric alkynylation of aliphatic and aromatic aldehydes, to prepare the corresponding propargylic alcohols in high yields with up to 99% ee. 相似文献
6.
Du-Ming Ji 《Tetrahedron letters》2009,50(24):2952-2955
An InBr3-catalyzed direct and efficient alkynylation of nitrones with terminal alkynes was developed. The process enables practical synthesis of a wide range of synthetically useful N-hydroxy-propargyl amine derivatives in good yields under mild conditions. The application of this method to optically active propargylic N-hydroxyamines syntheses was also described. With chiral nitrones, good diastereoselectivities were obtained. Moreover, the first chiral indium(III) complex-catalyzed asymmetric alkynylation of nitrone was achieved with moderate enantioselectivity. 相似文献
7.
Dan Jiang Dr. Pei Tang Dr. Qiuyuan Tan Zhao Yang Dr. Ling He Prof. Min Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(68):15830-15834
An efficient and catalytic asymmetric alkynylation of isatins has been developed using a bifunctional amidophosphine-urea/AgBF4 complex as the catalyst. By a combination of metal catalysis and organocatalysis, excellent enantioselectivities (up to 99 % ee) and good yields are achieved. A wide range of both terminal alkynes and isatins are tolerated by this new catalyst system, providing access to structurally diverse propargylic alcohols with tetrasubstituted stereogenic centers in high efficiency. 相似文献
8.
Zhou Ji-Cai Zhao Lei Li Yuan Fu Ding-Qiang Li Zi-Cheng Huang Wen-Cai 《Research on Chemical Intermediates》2017,43(7):4283-4294
Research on Chemical Intermediates - A practical synthesis of propargylic alcohols was developed by alkynylation of aldehydes mediated by zinc and allyl bromide. Aromatic, aliphatic and vinyl... 相似文献
9.
Paweł Czerwiński Edyta Molga Prof. Luigi Cavallo Dr. Albert Poater Dr. Michał Michalak 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(24):8089-8094
An efficient and easily scalable NHC–copper(I) halide‐catalyzed addition of terminal alkynes to 1,1,1‐trifluoromethyl ketones, carried out on water for the first time, is reported. A series of addition reactions were performed with as little as 0.1–2.0 mol % of [(NHC)CuX] (X=Cl, Br, I, OAc, OTf) complexes, providing tertiary propargylic trifluoromethyl alcohols in high yields and with excellent chemoselectivity from a broad range of aryl‐ and more challenging alkyl‐substituted trifluoromethyl ketones (TFMKs). DFT calculations were performed to rationalize the correlation between the yield of catalytic alkynylation and the sterics of N‐heterocyclic carbenes (NHCs), expressed as buried volume (%VBur), indicating that steric effects dominate the yield of the reaction. Additional DFT calculations shed some light on the differential reactivity of [(NHC)CuX] complexes in the alkynylation of TFMKs. The first enantioselective version of a direct alkynylation in the presence of C1‐symmetric NHC–copper(I) complexes is also presented. 相似文献
10.
Wenjin Yan Peng Li Jingchao Feng Dong Wang Shaoqun Zhu Xianxing Jiang Rui Wang 《Tetrahedron: Asymmetry》2010,21(16):2037-2042
On the basis of the phenomenon of self-assembly catalysis, a tridentate ligand was designed and synthesized in two steps. The application in alkynylation of N-(diphenylphosphinoyl) imines gave the expected products. Aromatic, heteroaromatic N-(diphenylphosphinoyl) imines were employed and gave optically active propargylic amines in good yields (up to 89%) and excellent enantioselectivities (up to 96%) by a simple experimental procedure. The direct use of sulfone amides in the alkynylation of N-(diphenylphosphinoyl) aliphatic imines made this method very attractive. 相似文献
11.
A C2-symmetric bisoxazolidine derived from aminoindanol has been successfully applied in the asymmetric alkynylation of aldehydes. The ligand is readily available, has a wide substrate scope, and catalyzes the formation of chiral propargylic alcohols with excellent yields and enantioselectivties. 相似文献
12.
Dr. Zhi-Min Chen Christine S. Nervig Dr. Ryan J. DeLuca Prof. Matthew S. Sigman 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(23):6751-6754
An enantioselective redox-relay Heck alkynylation of di- and trisubstituted alkenols to construct propargylic stereocenters is disclosed using a new pyridine oxazoline ligand. This strategy allows direct access to chiral β-alkynyl carbonyl compounds employing allylic alcohol substrates in contrast to more traditional conjugate addition methods. 相似文献
13.
Ping-Yu Wu Hsyueh-Liang Wu Ying-Ying Shen Biing-Jiun Uang 《Tetrahedron: Asymmetry》2009,20(16):1837-1841
This investigation describes that in the presence of 2.5 mol % of (?)-2-exo-morpholinoisobornane-10-thiol (MITH) 1, catalytic asymmetric alkynylation of aldehydes gives enantioenriched propargylic alcohols with good enantioselectivities. 相似文献
14.
Quangang Chen Yu Tang Tianyu Huang Prof. Dr. Xiaohua Liu Dr. Lili Lin Prof. Dr. Xiaoming Feng 《Angewandte Chemie (International ed. in English)》2016,55(17):5286-5289
The highly enantioselective alkynylation of isatins, catalyzed by a bifunctional guanidine/CuI catalyst under mild reaction conditions, is described. The reaction is broad in scope with respect to alkyl/aryl‐substituted terminal alkynes and substituted isatins, thus affording bioactive propargylic alcohols in excellent yields and enantioselectivities. 相似文献
15.
Ferrocenyl-substituted aziridinylmethanol (Fam-1) has been used as a chiral catalyst with titanium for enantioselective alkynylation of aromatic, heteroaromatic, aliphatic, and alpha,beta-unsaturated aldehydes to give the corresponding propargylic alcohols in up to 96% yield and 96% ee. The ligand can be prepared easily and recycled. 相似文献
16.
A new Lewis acid, Zn(ODf)2, was first prepared from commercially available 3,3,4,4-tetrafluoro[1,2]oxathietane 2,2-dioxide in four steps with 56% yields and also was applied to catalyze highly enantioselective alkynylation of aldehydes in the presence of ligand (1S,2S)-3-(tert-butyldimethylsilyloxyl)-2-N,N-dimethylamino-1- (p-nitrophenyl)-propane-1-ol or ligand (-)-N-methylephedrine to afford the corresponding propargylic alcohols in high yields with up to 99% ee. 相似文献
17.
A General Access to Propargylic Ethers through Brønsted Acid Catalyzed Alkynylation of Acetals and Ketals with Trifluoroborates
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Matthew Baxter Prof. Dr. Yuri Bolshan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(39):13535-13538
A general Brønsted acid catalyzed methodology for the alkynylation of acetals and ketals with alkynyltrifluoroborate salts has been developed. The reaction proceeds rapidly to afford valuable synthetic building block propargylic ethers in good to excellent yields. Unlike Lewis acid catalyzed transformations of trifluoroborates, this approach does not proceed via unstable organodifluoroborane intermediate. As a result, the developed methodology features excellent functional group tolerance and good atom economy. 相似文献
18.
Takahiro Nishimura 《Tetrahedron letters》2011,52(17):2185-2187
Oxidative alkynylation of acrylate esters with propargylic alcohols giving conjugated enyne esters was realized by use of a diene-rhodium catalyst. Propargylic alcohols were found to be useful alkynylating reagents in the present reaction to produce alkynylrhodium species via carbon-carbon bond cleavage. An excess of the acrylate ester worked as a hydride acceptor to reproduce the active rhodium species. 相似文献
19.
A Highly Efficient Gold‐Catalyzed Photoredox α‐C(sp3)H Alkynylation of Tertiary Aliphatic Amines with Sunlight
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Dr. Jin Xie Dr. Shuai Shi M. Sc. Tuo Zhang M. Sc. Nina Mehrkens Dr. Matthias Rudolph Prof. Dr. A. Stephen K. Hashmi 《Angewandte Chemie (International ed. in English)》2015,54(20):6046-6050
A new α‐C(sp3)? H alkynylation of unactivated tertiary aliphatic amines with 1‐iodoalkynes as radical alkynylating reagents in the presence of [Au2(μ‐dppm)2]2+ in sunlight provides propargylic amines. Based on mechanistic studies, a C? C coupling of an α‐aminoalkyl radical and an alkynyl radical is proposed for the C(sp3)? C(sp) bond formation. The mild, convenient, efficient, and highly selective C(sp3)? H alkynylation reaction shows excellent regioselectivity and good functional‐group compatibility. A scale‐up to gram quantities is possible with sunlight used as a clean and sustainable energy source. 相似文献
20.
Direct nucleophilic addition of terminal alkynes comprising an epoxy group to aldehydes and ketones is reported with BuLi or lithium diisopropylamide for the generation of the corresponding lithium acetylides. This alkynylation reaction tolerates a wide variety of different functional groups (e.g., alcohols, silyl ethers, halides, double bonds) in the carbonyl compound, as well as in the acetylenic nucleophile, and furnishes highly functionalized propargylic alcohols in good‐to‐excellent yields. The method is particularly useful for the regioselective introduction of an epoxide function into multiply unsaturated target molecules. 相似文献