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91.
[reaction: see text] The conjugate addition of dithiols to bis-ynones generates a versatile masked 1,3,5-triketone platform. These functional units are useful intermediates for the synthesis of oxygen-containing heterocycles commonly found in polyketide natural products. The tetrahydropyranyl fragments of the marine macrolides Lyngbouilloside and Callipeltoside A have been synthesized with use of this methodology. 相似文献
92.
Helen C. Aspinall Oliver BeckinghamMichael D. Farrar Nicholas Greeves Christopher D. Thomas 《Tetrahedron letters》2011,52(40):5120-5123
A diverse range of chiral and achiral oxazolyl ligands, which have many applications including catalysis and luminescent devices, are synthesized simply in three steps from readily available and inexpensive phenol and amino alcohol starting materials. The method can be applied to ligands with electron-donating/-withdrawing and sterically demanding/undemanding substituents, and can conveniently be scaled up to >25 g of product. 相似文献
93.
Abdolreza Rezaeifard Maasoumeh Jafarpour Hossein KavousiMahboubeh Alipour Helen Stoeckli-Evans 《Polyhedron》2011,30(13):2303-2309
Benzyltributylammonium periodate (BzBu3NIO4) was prepared easily in high yield in neat water. The compound crystallized with two cations and two anions per asymmetric unit and a space group of Pna21 was determined by single-crystal X-ray diffraction. It was used practically in the clean and selective epoxidation of olefins and oxygenation of saturated hydrocarbons catalyzed by manganese (III) porphyrins in water/ethanol as a green media. The catalyst could be reused without noticeable loss of activity, and the oxidant’s by-product (BzBu3NIO3) could also be reused. The efficiency of the oxidation system depends critically upon the steric hindrances and electronic structures of both the nitrogen donors and Mn-catalysts. Some evidences suggest the involvement of a high valent Mn-oxo species as well as a six-coordinate [(L)(Por)Mn-OIO3] complex in the oxidation reactions. 相似文献
94.
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96.
J. J. A. Wijs G. D. Elsdon J. R. Stubbs H. Lührig H. Atkinson A. Azadian G. Spitzer F. W. Epple C. H. Manley H. S. Shrewsbury L. V. Cocks E. Nightingale L. Hoton D. W. Steuart P. Smith G. H. Leopold W. J. de Mooy G. van B. Gilmour S. H. Blichfeldt T. Thornley E. L. Smith H. P. Kaufmann E. R. Bolton und C. Revis 《Fresenius' Journal of Analytical Chemistry》1930,80(7-8):303-314
Ohne Zusammenfassung 相似文献
97.
98.
In this work, the synthetic utility of the Ferrier reaction to access S-linked disaccharides and S-linked glycoamino acids has been probed. Significantly, entry to a range of 1,4- and 1,6-S-linked disaccharides has been achieved using glycals derived from glucose and galactose, and sulfur containing coupling partners derived from methyl α-d-glucopyranoside. Access to S-linked glycoamino acids and glycopeptides has also been achieved using protected cysteine and homocysteine coupling partners within the Ferrier reaction. Functionalisation of the Ferrier products, for example, via dihydroxylation using OsO4 or amino acid coupling, and deprotection of the targets have also been achieved. In this way, entry to materials of interest as mimics of biologically interesting disaccharides and glycopeptides has been realised, including targets derived from rare sugars such as talopyranose and gulopyranose. 相似文献
99.
100.
Jean-Marc Renaud Georges Tsoupras Helen Stoeckli-Evans Raffaele Tabacchi 《Helvetica chimica acta》1989,72(6):1262-1267
The novel allenic epoxycyclohexanes 1 , and related compounds 2 and 3 have been isolated from the culture medium of Eutypa lata. Their structures were established by combination of spectroscopic and chemical techniques. Biogenetic origin and biological activity of these compounds are also discussed. 相似文献