共查询到20条相似文献,搜索用时 31 毫秒
1.
The sensitized photooxygenation of vinylarenes and gave the corresponding 1,4-endoperoxides which were decomposed under mild conditions into quinone methides bearing ester function at the exocyclic carbon. 相似文献
2.
The vinylbromides and are allowed to react ith AgBF4 and AgPF6 in the presence of various olefins in CH2Cl2 as the solvent. Except for the reaction of cyclopentene with all other olefins used, react with vinyl cation to form the cycloaddition products , and in high yields. 相似文献
3.
Douglas E. McIntyre D.John Faulkner Donna Van Engen Jon Clardy 《Tetrahedron letters》1979,20(43):4163-4166
The major antibacterial metabolite in the sponge sp. was shown to be an isoquinoline quinone, renierone (). The structure of renierone () was defined by X-ray crystallography. 相似文献
4.
Photochemical cycloaddition of cyclopentene with enone esters containing different chiral auxiliaries yielded anti and syn adducts and in good yield and with moderate to high (79%) enantiomeric excesses. 相似文献
5.
A short-step synthesis of , the right-hand half of antibiotic saframycin (), is described. The key steps of this synthesis are the acid catalyzed intramolecular double cyclization of and the oxidative demethylation of to the quinone (). 相似文献
6.
Theodorus A Van Der Knaap Theodorus C Klebach Foppe Visser Rimmer Lourens Friedrich Bickelhaupt 《Tetrahedron》1984,40(6):991-997
Cycloaddition reactions of mesityl(diphenyliiifithylene)phosphine () were Investigated. With several dienes, no Diels-Alder reactions were oEserved. With azides, diphenyidiazomethane and 2,4,6-trimethylbenzonitrile oxide, the corresponding cycloadducts (were obtained. In the case of phenyl azide, a competing Staudinger reaction occurred leading to . 相似文献
7.
A. Zanarotti 《Tetrahedron letters》1982,23(38):3963-3964
Vinyl quinone methide () reacts with polyphenols to give cinnamylphenols () and neo-flavanoids (). Oxidation of cinnamylphenol (b) leads to malvidin () via the isolated intermediate flav-3-en-3o1 (b). 相似文献
8.
Single oxygen can easily add to 1-(β-methoxyvinyl) naphthalene () with retention of sterochemistry to afford a stable 1,4-endoperoxide . Sensitized photooxygenation of β-methoxystyrene () gives mainly Diels-Alder adducts of -formylmethide quinone () which might be derived from initially formed 1,4-endoperoxide . 相似文献
9.
Besides a structural isomerization to the title compound undergoes a faster automerization as shown by D-labelling; the change in the ratio of rearrangements of to ring contracted points to conformational effects in the reorganizations of . 相似文献
10.
A short route to the 2-azabicyclo[3.3.1]nonan-7-one system is described. Condensation of 4-piperidones with diethyl 2-oxopropylphosphonate, followed by catalytic hydrogenation furnished the corresponding piperidylpropanones which were cyclized with mercuric acetate in acetic acid to the target target bicyclic ketones . The Fischer indole synthesis from afforded regioselectively the indole [3,2-f]morphan , a new heteromorphan type. 相似文献
11.
Mineichi Sudani Yoshio Takeuchi Eiichi Yoshii Tadashi Kometani 《Tetrahedron letters》1981,22(42):4253-4256
The title compound having the same relative configurations as granaticin() and U-58,431() was prepared either by dehydrogenative cyclization of the precursor or by pinacol cyclization of the dicarbonyl compound . 相似文献
12.
Tsutomu Kumagai Akihiko Tokida Kazuo Kidoura Osamu Seshimoto Toshio Mukai 《Tetrahedron letters》1982,23(8):873-876
The reactions of 1H-azepine derivatives ( and ) with singlet oxygen gave the [6+2] cycloadducts () and the [4+2] cycloadducts ( and ). The thermal and base-catalyzed rearrangements of the oxygen-adducts were investigated. 相似文献
13.
Herbert Muffler Guenter Siegemund Werner Schwertfeger 《Journal of fluorine chemistry》1982,21(2):107-132
4.5-Perfluoro-1.3-dioxolanes are available by reaction of 2(α-chloroalkoxy)perfluoro-carbonyl halides or -ketone with fluoride ions. A mechanism for the intramolecular ring- closure-reaction is proposed. Hydrogen atoms at C-2 in can be exchanged photochemically by chlorine. Starting from the 2-monochloro-derivatives the 2-monofluoro-4.5-perfluoro- 1.3-dioxolanes are formed by reaction with triethylamine- hydrofluoride. 相似文献
14.
Suzanne Butt H.Geoff Davies Michael J. Dawson Gordon C. Lawrence Jeff Leaver Stanley M. Roberts Michael K. Turner Basil J. Wakefield Wilfred F. Wall John A. Winders 《Tetrahedron letters》1985,26(41):5077-5080
Bicyclo[3.2.0]hept-2-en-6-one (1) was reduced with an alcohol dehydrogenase from and a whole cell system () with excellent substrate enantioselectivity: 7,7-dimethylbicyclo[3.2.0]hept-2-en-6-one (2) was similarly reduced using the 3α,20β-hydroxysteroid dehydrogenase from Streptomyces while furnished both 6S-alcohols (4a), (6b) with high optical purity. 相似文献
15.
Ratna Dasgupta Pranab R. Kanjilal Swapan K. Patra Manish Sarkar Usha Ranjan Ghatak 《Tetrahedron》1985,41(23):5619-5625
The efficacy of a new acid-catalyzed intramolecular C-alkylation has been demonstrated by the synthesis of 1-methyl-4--methoxyphenylbicyclo [2.2.2] octan-2-one () and 4--methoxyphenylbicyclo [2.2.2] octan-2-one () from easily accessible starting materials. The carbinol , derived from , undergoes facile rearrangement leading to 1--methoxyphenyl-4-methyl bicyclo [3.2.1] oct-3-ene (), which has been transformed to -1--methoxyphenyl-4-methylbicyclo [3.2.1] octan-3-one (). 相似文献
16.
The title compounds and were synthesized by the usual dithia[3.3]phane coupling and photodesulfurization route. Investigation of their physical properties established their molecular dimension and conformation. Transannular interaction disclosed by their electronic spectra was explained by MO calculations. 相似文献
17.
Reaction of 1-(2-nitrophenoxy)naphthalene or its β-isomer with triethylphosphite produces benzo[a]phenoxazines and , through the intermediate . 相似文献
18.
A sequence of formylation followed by a carbene insertion reaction has led to the stepwise introduction of additional ethano bridges into 4,5,7,8- tetramethyl [22](1,4)cyclophane (), providing syntheses of 5,7,8-trimethyl- [23](l,2,4)cyclophane (), a mixture of 5,8-dimethyl[24(1,2,4,5)cyclophane () and 5,7-dimethyl[24(1,2,3,5)cyclophane (, and-4-methyl[25](1,2,3,4,5)-cyclophane (). This route to completes a formal eight-step synthesis of [26](1,2,3,4,5,6)cyclophane (, superphane) with an overall yield of 17%. A Birch reduction of readily gave 12,15-dihydro-5,7,8-trimethyl[23](1,2,4)-cyclophane () in 85% yield. 相似文献
19.
Maria Luisa Gelmi Donato Pccar Pasqualina Trimarco Mariella Valsecchi Riccakdo Destro Marzia Ballabio 《Tetrahedron》1984,40(20):4025-4032
1R*, 4R*, 5S*, 5'S*-5'-Amino-1'-(4-nitrophenyl)-4',5'-dihydrospiro[bicyclo [2.2. 1]hept-2-ene[5.4]-1',2',3'-triazoles] have been obtained both by ?4 +2]-cycloaddition of cyclopentadiene to amino-methylene-1-(4-nitrophenyl)-4,5-dihydro-v-triazoles and by [3+2]-cycloaddition of 4-nitrophenylazide to 5-aminomethylene-2-norborenes . The configuration has been fully established by X-ray crystallographic analysis. The course of the cycloaddition and the thermal behaviour of are discussed. 相似文献
20.
Refluxing the oximes () of naphtho-[1,8-bc] pyran-3(2H)-one and () of 3 (2H)-benzofuranone with alcoholic hydrogen chloride give the corresponding α-alkoxy-ketones , , and α-chloroketone respectively. This transformation appears to be related to the acid conversion of N-aryhydroxylamines to o. and p. substituted anilines (BAMBERGER réarrangement. 相似文献