共查询到20条相似文献,搜索用时 703 毫秒
1.
Dong Yamato 《Journal of inclusion phenomena and macrocyclic chemistry》1998,32(2-3):195-207
A new type of host is introduced: homocalix[3]arenes containing three aromatic units. Phane synthesis leading to molecules which may be termed, in the most general sense, homocalix[3]arenes, are outlined in a brief overview. The design, synthesis, conformations and host properties of homocalix[3]arenes are described in detail. 相似文献
2.
A biomimetic synthesis of shimalactone A and B is described. Its key features are an unprecedented acid-catalyzed cyclization of a dienyl beta-ketolactone and a Stille coupling/8pi-6pi electrocyclization cascade to create the oxabicyclo[2.2.1]heptane and bicyclo[4.2.0]octadiene, respectively. The synthesis is convergent and void of protecting groups. 相似文献
3.
[reaction: see text] A new method for the synthesis of substituted pyranone hemiketals from dioxanorbornanes via SmI(2) is described. Also reported is a synthesis of spiro[4.5]ketals from analogous intermediates via acid-promoted deprotection/ketalization. 相似文献
4.
Shyamalee GogoiMandakini Dutta Junali GogoiRomesh Chandra Boruah 《Tetrahedron letters》2011,52(7):813-816
A microwave-promoted and base-catalyzed synthesis of cycl[3.2.2]azines is accomplished in water via a three-component reaction (3-CR) of 2-picoline, α-bromoacetophenone and alkyne. The extension of the methodology to the synthesis of steroidal and carbocyclic cycl[3.2.2]azine is also reported. 相似文献
5.
The first total synthesis of (+)-frondosin A was accomplished in 19 longest linear and 21 total steps from commercially available materials. The key features of the synthesis include a Ru-catalyzed [5+2] cycloaddition, a Claisen rearrangement, and a ring expansion to construct the core of the frondosin A in a diastereoselective and regioselective fashion. This is the first application of a Ru-catalyzed [5+2] cycloaddition in the total synthesis of a natural product. Through this synthesis, the absolute configuration of (+)-frondosin A was established. 相似文献
6.
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
7.
A facile synthesis of benzo[d]benzo[2,3][1,4]diazepino[1,7-b] isothiazole, a new heterocyclic ring system is reported. 相似文献
8.
[reaction: see text] A conceptually new and highly versatile approach to bicyclo[5.3.0]decanes, based on dichloroketene cycloaddition-diazoalkane ring expansion, is disclosed, and its relevance to natural product synthesis is demonstrated through the preparation of three guaiane sesquiterpenes. A concise total synthesis of a guaian-8,12-olide, 6-deoxygeigerin, highlights the effectiveness of the new methodology. 相似文献
9.
Lan-Ying Qin Andrew G. ColeAxel Metzger Kurt W. SaionzIan Henderson 《Tetrahedron letters》2011,52(8):849-852
A synthesis of novel substituted 3,8,11-triazaspiro[5,6]dodecan-7-ones using a combination of solution-phase and solid-phase chemistries is described. A solution-phase approach was used to produce a key piperidine intermediate that was then incorporated into a solid-phase synthesis. The combined synthetic strategy was applied to provide a series of substituted 3,8,11-triazaspiro[5,6]dodecan-7-ones in good yield and high purity. 相似文献
10.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(42):13325-13329
A cobalt‐catalyzed dual C(sp3)−H activation strategy has been developed and it provides a novel strategy for the synthesis of bicyclo[4.1.0]heptanes and bicyclo[3.1.0]hexanes. A key to the success of this reaction is the conformation‐induced methylene C(sp3)−H activation of the resulting cobaltabicyclo[4.n.1] intermediate. In addition, the synthesis of bicyclo[3.1.0]hexane from pivalamide, by a triple C(sp3)−H activation, has also been demonstrated. 相似文献
11.
[reaction: see text] A facile synthesis of bisformylated calix[4]arenes via ipso substitution of p-tert-butylcalix[4]arenes through treatment with hexamethylenetetramine/trifluoroacetic acid is described. Under identical conditions, p-tert-butylcalix[4]arene tetramethyl ether 4 gives proximally substituted bisformylated derivative 4a in a pinched cone conformation. 相似文献
12.
Jinesh M. KuthanapillilSreeja Thulasi Rani RajanK. Syam Krishnan E. SureshK.V. Radhakrishnan 《Tetrahedron》2011,67(6):1272-1280
A new and highly versatile approach towards the synthesis of bicyclo[6.3.0]undecanes and bicyclo[5.3.0]decanes was accomplished. The methodology adopted involved [6+3] and [3+2] cycloaddition reactions of pentafulvenes with 3-oxidopyridinium betaines generated either by the action of a base on the pyridinium salt or thermally from pyridinium betaine dimer. These well-functionalized bicyclo[6.3.0]undecanes and bicyclo[5.3.0]decanes offer a wide range of synthetic options, which can be expected to translate into a variety of rapid and efficient synthesis of natural products. 相似文献
13.
Tan L Yasuda N Yoshikawa N Hartner FW Eng KK Leonard WR Tsay FR Volante RP Tillyer RD 《The Journal of organic chemistry》2005,70(20):8027-8034
[Chemical reaction: See text] A Et3Al mediated intramolecular epoxide opening, cyclopropanation reaction is described. The transformation provided highly functionalized bicyclo[3.1.0]hexane systems in high efficiency and with perfect H or F endo selectivity. Application of this reaction to the synthesis of mGluR2/3 agonist 1 (43% overall yield) and a few intermediates suitable for the synthesis of other bicyclo[3.1.0]hexane mGluR2/3 agonists is discussed. 相似文献
14.
[reaction: see text]A traceless solid-phase synthesis of cyclopenta[c]-4H-chromen-8-ol, benzo[d]cyclopenta[e]-3H-3-azin-8-ol, and other 11-heterosteroids via the fulvene hetero [6 + 3] cycloaddition is described. 相似文献
15.
GONG Jun-Fang WU Yang-Jie Véronique Micheletb Jean-Pierre Genêt b 《有机化学》2003,23(Z1):382-383
The construction of stereodefined, highly substituted tetrahydropyrans has attracted a lot of interest over the years since they constitute ubiquitous fragments of numerous biologically active natural products.[1] During the course of our synthetic studies toward ambruticin, a fascinating antibiotic[2] which came back in the front scene with three recent total synthesis, [3] we have been interested in the synthesis of 2,3,4,6-tetrasubstituted tetrahydropyrans 5 (Scheme 1). [4] Moreover, this kind of subunit is found to be embedded in several other natural products such as lasonolide A, polycavernoside A, ratjadone, or concanamycin A. 相似文献
16.
A new [2 + 2 + 2] approach to construct GPI molecules through the efficient synthesis of glucosamine-inositol and tetramannose intermediates led to a total synthesis of a GPI-anchor of Trypanosoma cruzi, and also afforded a key intermediate for the synthesis of valuable [4-deoxy-Man-III]-GPI analogues. 相似文献
17.
Sourav Biswas Christopher S. Qiu Louise N. Dawe Yuming Zhao Graham J. Bodwell 《Angewandte Chemie (International ed. in English)》2019,58(27):9166-9170
A new synthetic strategy (contractive annulation) for the synthesis of highly strained cyclophanes has been conceived and its viability has been demonstrated through a nine‐step synthesis of [2](6,1)naphthaleno[1]paracyclophane from [2.2]paracyclophane. 相似文献
18.
[structures: see text] A stereoselective synthesis of 2,3,5,6-tetra- and 2,3,4,5,6-pentasubstituted piperidines was achieved from oxidative cleavage of 2-aza-bicyclo[2.2.2]octene Diels-Alder adducts derived from N-protected 2-methyl-1,2-dihydropyridine. A chiral auxiliary mediated asymmetric synthesis of the pentasubstituted piperidine is also demonstrated. This methodology incorporates orthogonal protecting groups, thus providing a piperidine scaffold with easily modified points of diversity. 相似文献
19.
A facile solid phase synthesis of 2,4,6,7-tetrasubstituted pyrrolo[2,3-d]pyrimidines is described. The synthesis involves a highly efficient five-step route starting from resin-bound dimeric peptoids. To demonstrate the versatility of our method, a representative library of 108 tetrasubstituted pyrrolo[2,3-d]pyrimidines of high quality was synthesized. 相似文献
20.
Sreeja Thulasi Jisha Babu Adarsh Babukuttannair Viji Sreemathi Ramavarma Luxmi Varma 《Tetrahedron》2010,66(27-28):5270-5276
A seemingly ipso-like nucleophilic substitution of the upper rim of p-tert-butylcalix[4]arene is accomplished by an indirect method involving calix[4]arene derived bis(spirodienone). This method not only provides both mono and 1,3-diaryloxy calixarenes but also enables the synthesis of upper rim monothio substituted calix[4]arenes. A modification of the methodology can be successfully extended for the selective synthesis of mono- and 1,3-diquinone calix[4]arenes having free hydroxyl groups at the lower rim, in fewer steps. 相似文献