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1.
[reaction: see text] A linear sequence was used to synthesize (+)-lineatin in 14 steps and 14% overall yield from a homochiral 2(5H)-furanone. Key steps of this synthetic approach feature the diastereoselective construction of a cyclobutene through a photochemical [2 + 2] cycloaddition and a regiocontrolled oxymercuration reaction. 相似文献
2.
A concise total synthesis of the tricyclic terpene cyanthiwigin U has been accomplished in 12 steps and 17% overall yield. The key step of the synthesis is a two-directional tandem metathesis reaction that forms the cyclohepta[e]indene core from a readily available bicyclo[2.2.2]octene. 相似文献
3.
An efficient, convergent synthesis of the core bicyclo[4.3.1]decane ring system of welwitindolinones is described. Key steps in the synthesis include an intramolecular palladium-catalyzed enolate arylation reaction to create the desired bicyclic skeleton and a Curtius rearrangement to install the bridgehead isocyanate unit. [reaction: see text] 相似文献
4.
Govender S Mmutlane EM van Otterlo WA de Koning CB 《Organic & biomolecular chemistry》2007,5(15):2433-2440
Readily available 2,2',6,6'-tetramethoxy-1,1'-biphenyl was transformed in 14 synthetic steps into the natural product cardinalin 3 using a bidirectional approach. One of the key steps was the formation of the cis-1,3-dimethylnaphtho[2,3-c]pyran ring. (+/-)-1,1'-[6,6'-Diallyl-5,5'-bis(benzyloxy)-1,1',3,3'-tetramethoxy-2,2'-binaphthalene-7,7'-diyl]diethanol was treated with O(2) in the presence of CuCl(2) and catalytic PdCl(2) to afford 5,5'-bis(benzyloxy)-7,7',9,9'-tetramethoxy-1,1',3,3'-tetramethyl-1H,1'H-8,8'-bibenzo[g]isochromene. Hydrogenation of this compound afforded 7,7',9,9'-tetramethoxy-cis-1,3-cis-1',3'-tetramethyl-3,3',4,4'-tetrahydro-1H,1'H-8,8'-bibenzo[g]isochromene-5,5'-diol in quantitative yield, which was converted in 3 steps to cardinalin 3. 相似文献
5.
[reaction: see text] During studies directed toward the total synthesis of garsubellin A, a concise stereocontrolled synthesis of the 18-epi-tricyclic compound 3 was achieved. Key steps were a one-pot stereoselective construction of the bicyclic lactone 23 followed by a formal migration to the bicyclo[3.3.1]nonane-1,3,5-trione and an intramolecular Wacker-type tetrahydrofuran ring formation. 相似文献
6.
[reaction: see text] Highly substituted fused coumarins can be prepared in two steps starting from the appropriate boronic acids and enol triflates. The synthesis of fused pyrano[2,3-d]pyrimidin-7-one (1) is a key example to demonstrate the potential of the method in the elaboration of new coumarin scaffolds. 相似文献
7.
[reaction: see text] The total synthesis of (+)-sparteine was accomplished from 2,5-norbornadione in 15 steps and 15.7% overall yield. The key steps were two ring-expansion reactions, one involving an intramolecular Schmidt reaction and one using a novel variant of the photo-Beckmann rearrangement. 相似文献
8.
Modica E Compostella F Colombo D Franchini L Cavallari M Mori L De Libero G Panza L Ronchetti F 《Organic letters》2006,8(15):3255-3258
[Structure: see text] The C-sulfatide 1b was synthesized through a [2,3]-Wittig sigmatropic rearrangement and a Horner-Wadsworth-Emmons olefination as the key steps. The C-analogue 1b is less immunogenic than natural sulfatide 1a, but induces a preferential secretion of the proinflammatory cytokine IFN-gamma. 相似文献
9.
[reaction: see text] The p-benzoquinone shown is converted to the novel hexacyclic triterpene salvadione-A in four steps. 相似文献
10.
Vivek Badarinarayana 《Tetrahedron letters》2007,48(14):2607-2610
An enantioselective formal total synthesis of the pyrrolo[3,2-c]quinoline natural product martinellic acid has been achieved. The key steps involve a Pd-catalyzed aryl amidation reaction of a pyrroglutamate derivative, an intramolecular [3+2] azomethine ylide-alkene cycloaddition and a reductive ring opening reaction. 相似文献
11.
Mitsuaki Kodama Toshiya Takahashi Toshio Kurihara Shô Itô 《Tetrahedron letters》1980,21(29):2811-2812
3azzanene, the stereoisomer of trichodiene, isolated from a liverwort was synthesized with complete stereoselectivity in 8 steps (12% yield) starting from a known bicyclo[2.2.2]octane derivative. 相似文献
12.
[reaction: see text] The total synthesis of the antibacterial and antimycotic alkaloid hapalindole Q has been achieved in eight steps and 12.4% overall yield. The key step involves a regio- and diastereoselective Diels-Alder reaction to afford a bicyclo[2.2.2]oct-2-ene. This cycloadduct was subsequently dihydroxylated, cleaved, and converted to the natural product. 相似文献
13.
Bagley MC Chapaneri K Dale JW Xiong X Bower J 《The Journal of organic chemistry》2005,70(4):1389-1399
[reaction: see text] The synthesis of dimethyl sulfomycinamate, the acidic methanolysis product of the sulfomycin family of thiopeptide antibiotics, from methyl 2-oxo-4-(trimethylsilyl)but-3-ynoate is achieved in a 2,3,6-trisubstituted pyridine synthesis that proceeds with total regiocontrol in 13 steps by the Bohlmann-Rahtz heteroannulation of a 1-(oxazol-4-yl)enamine or in 12 steps and 9% yield by three-component cyclocondensation with N-[3-oxo-3-(oxazol-4-yl)propanoyl]serine and ammonia in ethanol. 相似文献
14.
[reactiojn: see text] The enantioselective synthesis of (+)-rogioloxepane A has been achieved in 21 steps from 1,5-hexadien-3-ol. The key steps in the synthesis are an asymmetric glycolate alkylation leading to the diene 2 and a subsequent ring-closing metathesis to construct the oxepene core. 相似文献
15.
[10]Cycloparaphenylene ([10]CPP) was selectively synthesized in four steps in 13% overall yield from commercially available 4,4'-diiodobiphenyl by using mono-I-Sn exchange, Sn-Pt transmetalation, I-Pd exchange, and subsequent oxidative coupling reactions. The single-crystal X-ray structure of [10]CPP is described. 相似文献
16.
An efficient, scaleable synthesis approach towards the spirocyclic oxindole analogue 1'-(tert-butoxycarbonyl)-2-oxospiro[indoline-3,4'-piperidine]-5-carboxylic acid (1) is described. The key steps are dianion alkylation and cyclization of ethyl 2- oxindoline-5-carboxylate (4) and demethylation of the resulting spirocyclic oxindole ethyl 1'-methyl-2-oxospiro[indoline-3,4'-piperidine]-5-carboxylate (5). The target compound was obtained in an overall yield of 35 % over eight steps without resorting to chromatographic purification. 相似文献
17.
Shotwell JB Krygowski ES Hines J Koh B Huntsman EW Choi HW Schneekloth JS Wood JL Crews CM 《Organic letters》2002,4(18):3087-3089
[reaction: see text] A highly convergent synthesis of the angiogenesis inhibitor luminacin D has been achieved in 13 linear steps (19 steps total, 5.3% overall yield) utilizing a samarium(II) iodide-mediated mixed tandem aldol/Evans-Tishchenko reaction to construct the carbohydrate precursor. The modular synthetic design will allow derivatization at key positions necessary for biochemical mode of action studies. 相似文献
18.
Starting from 8-oxabicyclo[3.2.1]oct-6-en-3-one and racemic 2,2-dimethyl-8-oxabicyclo[3.2.1]oct-6-en-3-one, the C1-C16 segment of the bryostatins has been synthesized in 30 steps and 9% overall yield (17 steps longest linear sequence). Fragment coupling by dithiane strategy and protecting group manipulations provided an advanced chemodifferentiated northern half segment. 相似文献
19.
《Tetrahedron: Asymmetry》2006,17(2):252-258
The stereoselective synthesis of 2-azabicyclo[2.2.1]heptane-1-carboxylic acid and 6-azabicyclo[3.2.1]octane-5-carboxylic acid, novel rigid bicyclic proline analogues, is reported. The synthesis was performed in five steps from the corresponding 2-cycloalken-1-ones. A known approach to 2,4-methanoproline is improved. The three amino acids constitute a library of conformationally constrained proline analogues, which can be used for the design of peptidomimetics and peptide models. 相似文献
20.
Aiming at a synthesis of spiro[2.4]hepta-4,6-dienes with a carbon substituent at C-4, we investigated solvolysis reactions of the thiatricycle 2, obtained from spiro[2.4]hepta-4,6-diene (1) and thiophosgene by [4 + 2] cycloaddition. With methanol or ethanol a mixture of the esters 7 and 8 was formed. Desulfurization of the thionoesters 8 gave methyl and ethyl spiro[2.4]hepta-4,6-diene-4-carboxylate (10a,b). The corresponding alcohol (11) was prepared from 10b by LiAlH(4) reduction. Ethenetetracarbonitrile combined with the 4-substituted spiro[2.4]hepta-4,6-dienes to give the [4 + 2] cycloadducts 12a-c. Diels-Alder reaction between 11 and 2-chloroacrylonitrile afforded the spiro(bicyclo[2.2.1]hept-5-ene-7,1'-cyclopropane) derivative 14a that was transformed in three steps to rac-10-hydroxycamphor (17). This synthesis of a bornane derivative opens opportunity for variations and thus may find further applications. 相似文献