共查询到20条相似文献,搜索用时 15 毫秒
1.
Jamookeeah CE Beadle CD Jackson RF Harrity JP 《The Journal of organic chemistry》2008,73(3):1128-1130
A flexible approach to functionalized and enantioenriched aziridines has been developed from an intermediate aziridinylmethyl tosylate. This protocol features a Cu-catalyzed Grignard substitution reaction that allows a range of functionalized organic fragments to be incorporated. Moreover, a convenient one-pot procedure is outlined that allows the trityl group to be exchanged for a range of common N-protecting groups. 相似文献
2.
The cycloadduct (5) , which is conveniently prepared by irradiation of (4), is converted a 4-step sequence, into the tricyclic ketone (2) and its epimer (2); the sequence formally completes a new total synthesis of (±)-zizaene (1) and its Me-epimer. 相似文献
3.
《Tetrahedron letters》1988,29(33):4039-4040
Tricyclic lactone 10, a potential intermediate for the synthesis of forskolin, was prepared from (±)-3-hydroxycyclocitral employing an intramolecular Michael addition as the key step. 相似文献
4.
Efficient ring cleavage of 9,10-dibromocamphor (3) provides a monocyclic hydroxyacid (5) which can serve as an intermediate in a new enantiospecific synthesis of estrone. 相似文献
5.
[reaction: see text] A short synthesis of intermediates possessing the tricyclic core of natural madangamines, bioactive alkaloids found in marine sponges, is described. The key reaction entails the condensation of the sodium salt of diethylacetonedicarboxylate with a dihydropyridinium salt derivative. This new approach is modeled on a biogenetic proposal linking madangamines to ircinals, related alkaloids occurring in sponges of the same order. 相似文献
6.
《Tetrahedron: Asymmetry》2007,18(21):2587-2597
The enantiospecific total synthesis of a komarovispirane, containing the complete carbon framework, trans-bicyclo[4.3.0]nonanespiro[8.1′]cyclohexane, of the spiroditerpene komarovispirone, starting from the readily available campholenaldehyde is described. 相似文献
7.
Guo-Hua Chu Bertrand Le Bourdonnec Minghua Gu Christopher T. Saeui Roland E. Dolle 《Tetrahedron》2009,65(27):5161-1506
A general and efficient synthetic approach to tricyclic spiroketones of interest as useful scaffolds in drug discovery was developed. Starting from commercially available benzyl 4-oxo-1-piperidinecarboxylate (5), spirocyclic tetralone 4, spirocyclic indanone 14, and spirocyclic benzocycloheptanone 15 were synthesized via six reaction steps in excellent overall yield. 相似文献
8.
Xuanjia Peng 《Tetrahedron letters》2004,45(16):3283-3285
A novel approach has been found and the first total synthesis of (±)-Salvirecognine was accomplished by using it. In which intramolecular cyclization and Friedel-Crafts alkylation took place simultaneously to afford key intermediates for synthesis of aromatic tricyclic diterpenoids. 相似文献
9.
The barbatenes (e.g. 3) and a number of other sesquiterpenes afford a novel rearrangement product on treatment with CF3CO2H. This substance, designated isobarbatene, is shown to have structure 6, the result of a bicyclo-[3.2.1]→[2.2.2]→[3.2.1] rearrangement followed by an exo Me shift and deprotonation. The structure assignment is based on spectral and chiroptical data for olefin 6 and its degradation products 8,9 and 10. 相似文献
10.
An efficient stereoselective approach to the construction of a hydrindane derivative having a bridged lactone is described toward the synthesis of the sesquiterpenes of the seco-prezizaane family. The key step involves RO-RCM of a norbornene derivative. 相似文献
11.
In this paper we describe the stereoselective synthesis of functionalized lactam 7 via two enantiospecific piperidine-forming techniques and its employment in a general synthetic approach to Nuphar alkaloids. Specifically, the formation of piperidine 18 by formal [3 + 3] cycloaddition and stepwise annelation processes is described; the latter technique was found to be significantly more efficient than the Pd-catalyzed TMM addition process. Finally, exploitation of the exocyclic alkene installed in the piperidine-forming reaction in the transformation of 18 to (-)-deoxynupharidine ((-)-2), (-)-castoramine ((-)-3), and (-)-nupharolutine ((-)-4) via intermediate lactam 7 is delineated. 相似文献
12.
Three new halogenated tricyclic sesquiterpenes, omphalaurediol (1), rhodolaurenones B (2) and C (3) were isolated together with nine known haloganated sesquiterpenes such as rhodolaurenone A (4), rhodolaureol (5), isorhodolaureol (6), (?)-laurencenone D (7), elatol (8), (+)-deschloroelatol (9), cartilagineol (10), (+)-laurencenone B (11) and 2-chloro-3-hydroxy-α-chamigren-9-one (12) from a population of Bornean red algae Laurencia majuscula. The structures of three new metabolites were determined based on their spectroscopic data (IR, 1D and 2D NMR, and MS). These compounds showed antibacterial activity against three human pathogenic bacteria (Escherichia coli, Salmonella typhi and Vibrio cholera). 相似文献
13.
Alan R. Kennedy William J. Kerr Mark McLaughlin Peter L. Pauson 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(11):1316-1318
A completely novel and direct route towards the synthesis of the natural sesquiterpenes α-cedrene and β-cedrene delivered the compounds (3β,3aβ,7β)-(±)-6,6-ethylenedioxy-3,8,8-trimethyl-2,3,3a,4,5,6,7,8-octahydro-3a,7-methanoazulen-2-one, C16H22O3, and (3β,3aβ,7β,8aα)-(±)-6,6-ethylenedioxy-3,8,8-trimethyl-1,2,3,3a,4,5,6,7,8,8a-decahydro-3a,7-methanoazulen-2-one, C16H24O3, at key stages of the preparative programme. Structural elucidation showed the latter compound to have added an H atom to the same face of the cyclopentenone ring as that occupied by the methyl substituent, and also allowed correct isomer identification for further reaction. 相似文献
14.
Wenchun Chao 《Tetrahedron letters》2006,47(23):3815-3818
Employing an intramolecular N-acylketiminium ion/olefin hetero Diels-Alder reaction, and a ring closing metathesis of a vinyl chloride as pivotal steps, it is possible to directly access the pyridoquinoline tricyclic ring system of the marine alkaloids cylindrines B and J. 相似文献
15.
A concise enantiospecific synthesis of the pine beetle pheromone (+)-hydroxy-exo-brevicomin was achieved from l-(+)-tartaric acid in high yield. The key step involves the reduction of a keto-Weinreb amide derived from tartaric acid. 相似文献
16.
17.
An enantiospecific and stereo- and functional group diversity oriented approach to eudesmane, eremophilane and agarofuran sesquiterpenoids from (−)-carvone has been devised. RCM has been employed as the key reaction to generate the highly functionalized eudesmane framework. Further elaboration of the eudesmane framework to agarofurans and biogenetic-type rearrangement to eremophilanes is outlined. 相似文献
18.
A simple and efficient one-pot protocol is accomplished to access tricyclic spiro dihydrofurans (4) by the reaction of β-enamino ketones (1) and dimedone (2) in ethanol followed by sequential addition of N-chlorosuccinimide at ambient temperature for the first time. The selectivity in desired product formation in good yields is the advantage of this protocol. 相似文献
19.
Liam Evans John Hedger Brian W. Skelton R. Thomas Williamson 《Tetrahedron letters》2010,51(41):5493-5496
Three new unusual sesquiterpenes (1-3) were isolated from the tropical rainforest basidiomycete, Marasmiellus troyanus and their structure elucidation was achieved by NMR spectroscopy, single-crystal X-ray structural analysis and a modified Mosher’s ester method to determine the absolute stereochemistry of compound 1. These unusual metabolites are probably derived from the caryophyllane class of sesquiterpenes and a possible biosynthetic route to these compounds is proposed. These small natural products represent the best possible features of chemical diversity, being chiral and exhibiting extensive functional group chemistry highlighting the value of natural products as a screening resource for therapeutics discovery programmes. 相似文献
20.
Fietz-Razavian S Schulz S Dix I Jones PG 《Chemical communications (Cambridge, England)》2001,(20):2154-2155
The absolute configuration of the recently identified sesquiterpene (+)-kelsoene was revised by chemical correlation with (R)-(+)-pulegone; the correct structure is (1R,2S,5R,6R,7R,8S)-2,8-dimethyl-6-(1-methylethenyl)tricyclo[5.3.0.0 (2,5)]decane. 相似文献