共查询到20条相似文献,搜索用时 28 毫秒
1.
Zheng Wang Hassan Elokdah Geraldine McFarlane Sherry Pan Madelene Antane 《Tetrahedron letters》2006,47(20):3365-3369
An efficient route to the biologically active naphthyl benzofuran derivative is described. The synthesis highlights a regioselective Suzuki coupling of a benzofuran and a dibromo substituted naphthalene. The scope of regioselective Suzuki coupling has been investigated. 相似文献
2.
Highly functionalized β-aminocyclohexanecarboxylate regio- and stereoisomers were synthesized from a bicyclic β-lactam by successive regioselective iodolactonization, stereo- and regioselective nitrile oxide cycloaddition, lactone ring-opening and isoxazoline ring-opening. 相似文献
3.
Full Functionalization of the Imidazole Scaffold by Selective Metalation and Sulfoxide/Magnesium Exchange 下载免费PDF全文
Christoph Sämann Estibaliz Coya Prof. Dr. Paul Knochel 《Angewandte Chemie (International ed. in English)》2014,53(5):1430-1434
A simple, flexible, and straightforward method for the functionalization of all the positions of the imidazole heterocycle through regioselective arylations, allylations, acylations, and additions to aldehydes is disclosed. Starting from the readily available key imidazole 1 , highly functionalized imidazole derivatives have been synthesized in a regioselective manner from directed metalations and a sulfoxide/magnesium exchange. Moreover, the selective N3‐alkylation followed by deprotection of N1 (trans‐N‐alkylation) allows the regioselective N‐alkylation of complex imidazoles. 相似文献
4.
Sebastián A. Testero 《Tetrahedron》2007,63(46):11410-11420
The ozonolysis of carbohydrate derived norbornene systems in participating solvents demonstrated that different remote controlling factors could induce the regioselective fragmentation of the primary ozonide. The exo norbornene series afforded a complete regioselective process. 相似文献
5.
Murakami N Sugimoto M Morita M Kobayashi M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2001,7(12):2663-2670
The first total synthesis of agosterol A, a modulator of multidrug resistance (MDR) mediated by P-gp and MRP1, and isolated from a marine sponge, was achieved from ergosterol by utilizing a regioselective epoxy-cleavage reaction and regioselective dehydroxylation as the key reactions. 相似文献
6.
A directing/protecting group designed for regioselective functionalization of partially-protected glucopyrannosides has been successfully used to prepare disaccharides in high yields. Most importantly, it has been demonstrated that highly regioselective and stereoselective glycosylation can be achieved when disarmed donors are employed. This study demonstrates the ability of directing/protecting group to induce regioselective glycosylation of carbohydrates and opens the field to the design of other DPGs for other monosaccharides. 相似文献
7.
Two synthetic routes to isocarbacyclin starting from furfural are described. One route involves the regioselective hydrogenation of the disubstituted olefin in the presence of two other olefinic double bonds, and the other includes the highly regioselective organocopper coupling with the allylic etectrophile as a key step. 相似文献
8.
Total Synthesis of Ellagitannins through Regioselective Sequential Functionalization of Unprotected Glucose 下载免费PDF全文
Hironori Takeuchi Dr. Kenji Mishiro Dr. Yoshihiro Ueda Yusuke Fujimori Dr. Takumi Furuta Prof. Dr. Takeo Kawabata 《Angewandte Chemie (International ed. in English)》2015,54(21):6177-6180
Short total syntheses of natural glycosides (ellagitannins) were performed through sequential and regioselective functionalization of the hydroxy groups of unprotected glucose. The key reactions are β‐selective glycosidation of a gallic acid derivative by using unprotected glucose as a glycosyl donor and catalyst‐controlled regioselective introduction of a galloyl group into the inherently less reactive hydroxy group of the glucoside. 相似文献
9.
[reaction: see text] A short synthesis of (+/-)-brazilin is reported. This synthesis uses several interesting and underutilized transformations including a regioselective dirhodium-catalyzed aryl C-H insertion, a regioselective IBX phenol --> o-quinone oxidation, a tautomerization of an o-quinone to a p-quinone methide, and an intramolecular aryl cyclization with a p-quinone methide. 相似文献
10.
Enantioselective and Regioselective Pyrone Diels–Alder Reactions of Vinyl Sulfones: Total Synthesis of (+)‐Cavicularin 下载免费PDF全文
Peng Zhao Prof. Dr. Christopher M. Beaudry 《Angewandte Chemie (International ed. in English)》2014,53(39):10500-10503
The total synthesis of (+)‐cavicularin is described. The synthesis features an enantio‐ and regioselective pyrone Diels–Alder reaction of a vinyl sulfone to construct the cyclophane architecture of the natural product. The Diels–Alder substrate was prepared by a regioselective one‐pot three‐component Suzuki reaction of a non‐symmetric dibromoarene. 相似文献
11.
Mejorado L Pettus TR 《Synlett : accounts and rapid communications in synthetic organic chemistry》2006,(19):3209-3214
A route enabling the synthesis of the stereo-triad of rishirilide B (1) from 2-hydroxy-3-methylnaphthalene-1,4-dione, is reported. Key transformations include the regioselective 1,2-Grignard addition to a tautomeric mixture of o- and p-quinones, regioselective carbamoylation of a tautomeric mixture, and a synopsis of the methods explored to convert various terminal vinyl ethers into the corresponding carboxylic acid by cleavage. 相似文献
12.
An efficient and regioselective synthesis of polysubstituted benzene derivatives was achieved via multicomponent reaction of a substituted cyclopropenone acetal and two alkyne molecules. The synthesis utilizes cyclopentadienone acetal as an intermediate and enables regioselective [2+2+2] assembly of the three-components into a benzene ring. A variety of polysubstituted benzene derivatives of synthetic and structural interest have been synthesized. 相似文献
13.
A novel methodology for the synthesis of trisubstituted allenes is reported. Lithiation of 1-aryl-3-alkylpropadienes and subsequent transmetalation with zinc bromide followed by Pd-catalyzed Negishi coupling reactions with halides afforded the corresponding trisubstituted allenes in a highly regioselective fashion with moderate to excellent yields. A plausible regioselective lithiation mechanism was proposed on the basis of deuterium labeling experiments. 相似文献
14.
Grégory Burzicki 《Tetrahedron》2009,65(27):5413-1917
This paper describes an efficient and regioselective synthetic route leading to new dihalobi- and terpyridines. We developed a strategy based on regioselective sequence of Suzuki-Miyaura cross-coupling reactions between bromopyridyl boronic acids and dihalopyridines and dihalobipyridines. The study of the influence of the nature and the position of the halogen atoms leads to prepare bromoiododerivatives to obtain good selectivities. 相似文献
15.
Blay G Bargues V Cardona L Collado AM Garcia B Munoz MC Pedro JR 《The Journal of organic chemistry》2000,65(7):2138-2144
Hydroxyester 2, easily obtained from santonin (1), has been transformed into 10 alpha-hydroxyguai-3-en-8,12-olide 6, a good intermediate for the synthesis of natural 8,12-guaianolides. Compound 6 was obtained from 2 by photochemical rearrangement of its acetyl derivative 7, stereoselective hydrogenation on Pd/C, reduction, regioselective elimination, hydrolysis, and lactonization. The synthesis of the natural guaianolides 3-5 was carried out in two sequences in which the regioselective elimination of a hydroxyl group at C10 with triflic anhydride or SOCl2 to afford, respectively, the endo or exo double bond on C10 and the regioselective opening of the C3-C4 alpha-epoxide were the key steps. 相似文献
16.
Dr. Luísa C. R. Carvalho Fausto Queda Cátia V. Almeida Santos Dr. M. Manuel B. Marques 《化学:亚洲杂志》2016,11(24):3468-3481
Chitin and chitosan are attractive biopolymers with enormous structural possibilities for chemical modification, creating platforms for new chemical entities with a broad scope of applications, ranging from material science to medicine. During the last few years, incredible efforts have been dedicated to the regioselective modification of these biopolymers paving the way for improved properties and tailored activities. Herein, the most recent advances in chitin/chitosan regioselective modification, reaction conditions, selectivity, and the impact on its applications are highlighted. Moreover, the recent focus on chitooligosaccharides, their regioselective and chemoselective functionalization, as well as their role in biological studies, including molecular recognition with several biological targets are also covered. 相似文献
17.
James R. Vyvyan Jennifer M. Oaksmith Bevin W. Parks Elaine M. Peterson 《Tetrahedron letters》2005,46(14):2457-2460
The total synthesis of heliannuol C and E from a common intermediate are described. Key steps in the synthesis include a regioselective aromatic Claisen rearrangement to install the (1-vinyl)-4-methyl-3-pentenyl substituent and regioselective biomimetic 7-endo and 6-exo phenol epoxide cyclizations to form the cyclic ether moieties. 相似文献
18.
The resolution of α- and β-anomers of glucopyranosides and galactopyranosides was achieved via enzyme-catalysed regioselective acylation. This two-step procedure to prepare pure α- and β-anomers of glycopyranosides would be most useful for the cases where glycosidases are not available or expensive to purchase. From a synthetic viewpoint, the regioselective acylation of glycopyranosides provides access to mono- and di-esters with well-defined substitution patterns. 相似文献
19.
Novel and promising thiophenone derivatives were synthesised by regioselective ring opening of activated thiomalic acid anhydrides, with a variety of active methylene nucleophiles via a C-acylation/cyclisation process involving an S-C bond formation. This regioselective approach could be moreover established by X-ray diffraction structure analysis. The thiolactone ring can act as valuable synthetic scaffold for the preparation of natural and synthetic compounds with important biological and pharmacological activities. 相似文献
20.
Allylindium reagents undergo facile and highly regioselective cross-coupling with benzylic and cinnamyl bromides in THF at room temperature without any catalyst producing terminal alkenes in high yields. The addition is highly regioselective and is found to provide γ-adducts in all reactions. 相似文献