共查询到20条相似文献,搜索用时 31 毫秒
1.
Aliphatic and aromatic amines react with 2- and 3-chlorostyrene in the presence of potassium tert-butoxide to give N-substituted 2,3-dihydroindoles in good yields. The combination of this domino-amination protocol with a suitable dehydrogenation reaction gives access to pharmacologically interesting indoles in a one-pot procedure. Overall product yields of N-substituted indoles >50% are obtained by this method starting from commercially available substrates. In addition to the intramolecular base-promoted amination of aromatic C-Cl bonds, metal-free intermolecular aminations of aryl chlorides with primary and secondary amines are described. The use of potassium tert-butoxide as base allows the synthesis of various anilines in good to excellent yields. Due to the formation of aryne intermediates, either N-substituted anilines or meta-substituted anilines are produced with excellent selectivities. 相似文献
2.
[reaction: see text] Treatment of the benzannulated enediyne 11 with potassium tert-butoxide in refluxing toluene for 12 h produced 15 via a cascade sequence of cyclization reactions. Two subsequent palladium-catalyzed intramolecular arylation reactions then afforded the bowl-shaped polycyclic aromatic hydrocarbon 16. The X-ray structures of 16 and two closely related molecules show the presence of significant curvatures. 相似文献
3.
Likhar PR Zirngast M Baumgartner J Marschner C 《Chemical communications (Cambridge, England)》2004,(15):1764-1765
Depending on the conditions the reaction of tris(trimethylsilyl)methoxysilane (1) with potassium tert-butoxide either in benzene and in the presence of 18-crown-6 or in THF gives either the crown ether adduct of potassium-methoxybis(trimethylsilyl)silane (2), or 2-methoxytetrakis(trimethylsilyl)disilanyl potassium (3). 相似文献
4.
Abstract: Aryl or alkyl propargyl ethers have been isomerized efficiently with good to excellent yield into corresponding allenyl ethers in the presence of potassium tert-butoxide under the microwave irradiation. 相似文献
5.
The benzannulated enediynyl propargylic alcohol 8 was prepared from 1-bromo-2-iodobenzene by two consecutive Sonogashira cross-coupling reactions. The subsequent transformation to mesylate 9 followed by treatment with 4-substituted pyridines 10 then furnished the benzannulated enediynes 11. On exposure of 11 to triethylamine, the indeno-fused quinolizinium salts 15 were produced in quantitative yield. Presumably the reaction proceeded through a 1,3-prototropic rearrangement to form the benzannulated enyne-allenes 12, which then underwent either a concerted Diels-Alder reaction or a two-step process involving a Schmittel cyclization reaction to form biradical 13 followed by an intramolecular radical-radical coupling to afford 14. A subsequent prototropic rearrangement then produced 15. Similarly, 21a and 21b were produced from 19a and 19b, respectively. The use of the Sonogashira reaction for cross-coupling between 1-iodo-2-(phenylethynyl)benzene (7) and 1-(2-propynyl)-1H-imidazole (25) followed by treatment of the resulting adduct with potassium tert-butoxide gave the indeno-fused imidazo[1,2-a]pyridine 24 in 98% yield. Similarly, the indeno-fused pyrido[1,2-a]indole 32 and 4H-quinolizin-4-one 35 were obtained by starting from 7 for cross-coupling with 1-(2-propynyl)-1H-indole (30) and 1-(2-propynyl)-2(1H)-pyridinone (33), respectively, followed by treatment with potassium tert-butoxide. 相似文献
6.
A practical and reproducible route for the preparation of 1,4,7,10,13,16,19-heptaazacyclohenicosane (1), 1,4,7,10,13,16-hexaazacyclooctadecane (2), and 1,4,7,10,13,17-hexaazacycloicosane (3) bearing a single N-(2-aminoethyl) pendant arm has been developed. Richman-Atkins cyclization in the presence of caesium carbonate was applied to construct the macrocycle from 3-benzoyl-N1,N5-ditosyl-3-azapentane-1.5-diamine and the appropriate fully N-tosylated N alpha, N omega-bis(2-mesyloxyethyl) tri- or tetra-amine. The benzoyl group was selectively removed with potassium tert-butoxide, and the exposed nitrogen atom was reacted with N-tosylaziridine. The tosyl protections were removed with hydrogen bromide in acetic acid, and the product was converted to a free base with the aid of a strong anion exchange resin (OH- form). 相似文献
7.
β,β-二烷硫基-α,β-不饱和酮类化合物作为一类具多反应中心的活泼中间体在有机合成中的应用,近20年来已引人注目并进行了深入广泛的研究~[1,2].以往的研究大多是针对β,β-二甲硫基-α,β-不饱和酮类化合物1进行的,而对结构相近的β,β-1,3-亚丙二硫基-α,β-不饱和酮类化合物2的研究较少.对于1类的合成,所用碱的选择至关重要~[1].实验证明叔丁醇钠和叔丁醇钾~[3~5]在1类的合成中效果较好.前文~[6]曾以六甲基二硅氨基锂(LHMDS)为碱高 相似文献
8.
Synthesis of substituted phenanthridinones and dibenzoazepinones has been realized from 2-halo-benzamides in the presence of potassium tert-butoxide and a catalytic amount of 1,10-phenanthroline or AIBN. This new carbon-carbon bond forming reaction gives direct access to various biaryl lactams containing six- and seven-membered rings chemoselectively. Carbon-carbon coupling seems to proceed by the generation of a radical in the amide ring which leads to C-H arylation of aniline. 相似文献
9.
A series of substituted aliphatic nitriles have been trimerized to their corresponding pyrimidine structures under solvent-free conditions in the presence of catalytic quantities of potassium tert-butoxide using a focused microwave reactor. Multigram quantities of the corresponding 4-aminopyrimidines have been prepared in high yields and purity following a simple and scaleable protocol. 相似文献
10.
Tarasova O. A. Nedolya N. A. Albanov A. I. Trofimov B. A. 《Russian Journal of Organic Chemistry》2017,53(1):130-133
Russian Journal of Organic Chemistry - Aromatization of 2-methyl-6-(methylsulfanyl)-5-phenyl-2,3-dihydropyridine in DMSO in the presence of potassium tert-butoxide is accompanied by dimerization... 相似文献
11.
Yagodkina M. S. Yakovenko G. G. Bol’but A. V. Vovk M. V. 《Russian Journal of Organic Chemistry》2017,53(4):634-636
Russian Journal of Organic Chemistry - Cascade cyclization of methyl 2-(azidomethyl)furan-3-carboxylate with 2-cyanoacetamides in the presence of 2 equiv of potassium tert-butoxide afforded a... 相似文献
12.
Rueping M Leiendecker M Das A Poisson T Bui L 《Chemical communications (Cambridge, England)》2011,47(38):10629-10631
A transition metal-free Heck-type cyclization/isomerization reaction has been developed. Mediated by potassium tert-butoxide and phenanthroline a variety of benzofuran derivatives have been synthesized. 相似文献
13.
Katritzky AR Hayden AE Kirichenko K Pelphrey P Ji Y 《The Journal of organic chemistry》2004,69(15):5108-5111
Reactions of secondary amides 2a-i with 1-chloro-1H-benzotriazole and triphenylphosphine give imidoylbenzotriazoles 3a-i. The treatment of 3a,b,e,g with silyl enol ethers 5a,b in the presence of potassium tert-butoxide provides a new general approach to enaminoketones 6a-h. 相似文献
14.
The C-H bond of benzene was directly arylated by reaction with aryl iodides in the presence of a catalytic amount of a pentamethylcyclopentadienyliridium complex and potassium tert-butoxide. 相似文献
15.
Kiesewetter MK Gard MN Reiter RC Stevenson CD 《Journal of the American Chemical Society》2006,128(49):15618-15624
The low temperature complete dehydrohalogenation of pentabromocyclododecene (C12H17Br5) with potassium tert-butoxide in THF followed by exposure to potassium metal leads to the formation of the anion radical of 1,5-di-trans-[12]annulene, which loses hydrogen and undergoes ring closure to form the anion radical of 11,12-dihydro-[8]annuleno-[6]annulene. This product can, in turn, be isolated as its neutral molecule via reoxidation with iodine. A [12]annulene obtained via the dimerization of 1,5-hexadiyne in the presence of 18-crown-6 and potassium tert-butoxide undergoes ring closure, with concomitant loss of hydrogen, to yield the heptalene anion radical. It follows that the heptalene anion radical precursor was the 1,7-di-trans isomer of [12]annulene. 相似文献
16.
The first stereoselective method of preparation of (E)-dienol phosphates from alpha,beta-ethylenic aldehydes is described. The key point is the stereoselective enolization of conjugated alkenals by potassium tert-butoxide in the presence of N-methylpyrrolidinone (NMP). 相似文献
17.
A stable zwitterionic radical can catalyze direct arylation of unactivated aromatic C-H bonds via a chain homolytic aromatic substitution mechanism in the presence of potassium tert-butoxide. 相似文献
18.
3,6-Dihydro-2H-pyrans and other, cyclic or acyclic, homoallyl ethers undergo smooth ring-opening through β-elimination when treated with lithium diisopropylamide in the presence of catalytic amounts of potassium tert-butoxide. 相似文献
19.
[reaction: see text] Indolylaryl and indolylheteroarylmaleimides, including bisindolylmaleimides, are easily prepared by the reaction of N-methylindole-3-glyoxylamide with methyl aryl acetates in the presence of potassium tert-butoxide in THF. 相似文献
20.
The regio- and diastereoselective silaboration of aromatic alkenes with a silylboron compound proceeds in the presence of a catalytic amount of potassium tert-butoxide, providing a complementary method to the corresponding transition metal-catalyzed reactions. 相似文献