Stereoselective Synthesis of C - Glycosides with a
نویسنده
چکیده
K . Karaghiosoff, G. Jochem. A. Schmidpeter, unpublished. S. Lochschmidt, A. Schmidpeter. Phosphorus Sulr;r 1986.29, 73-109. a) G. A. Gray, J. Am. Chem. Sac. 1973, 95. 7736-7742; b) G. Fronza, P. Bravo. C. Ticozzi, J. Orgunornet. Chem. 1978, f57, 299-310; c )M. Schlosser, T. Jenny, B. Schaub, Heteroat. Chem. 1990. 1, 151-156. If the phosphonio group at the C atom and the substituent at the P atom of a phosphaalkene arc fixed CIS to each other in a ring, then 'J(P,P) z 50 Hz. E. Fluck, G. Becker, B. Neumiiller. R. Knebl, G. Heckmann. H. Riffel, Z. Nuturjor.wh. B 1987, 42, 1213-1221. In Fdct, compound 5b stays ionic and the bromide ion does not associate with the two-coordinate phosphorus. The same applies to compound 5 c , which is generated from 3c and Et,NSiMe, and has NEt, instead of SCH,Ph and CIinstead of Br[4], for which similar "P NMR data were obtained. A. Schmidpeter, G. Jochem. K. Karaghiosoff, C. Robl, Angew. Chem. 1992, 104, 1420-1441; Angeu. Chem. In[. Ed. EngI. 1992, 31. 1350-1352. a) 2.4,6-Tri-tert-butylphenyldithioxophosphorane: R. Appel, F. Knoch, H. Kunze, Angew. Chem. 1983, 95, 1008-1009; Angew. Chem. Int. Ed. EngI. 1983. 22. 10041005. b) 2.6-Di-terf-butyl-4-methylphenyldithioxophosphorane: A. S. Ionkin, V. M. Nekhoroshkov, Y. Y Efremor, Izv. Akod. SSSR Ser. Khim. 1991, 1654-1656; Chemicul Abstructs 1991 t l 5 , 208 108s; see also [11 c]. c) 2,6-Bis(trifluoromethyl)phenyldithioxophosphorane: G. Grossmann. G. Ohms, H. Beckmann. K. Friedrich, E. Niecke, M. Nieger, R. Serwas. V. von der Gonna, W. W. Schoeller, Abstr. Xllth In!. ConJ. Phosphorus Chem., Toulouse, 1992. Proceedings: Phosphor u s , Sulfur Silicon Relut. Elem. 1993. 77, 248. X-ray diffraction crystal structure determination: Data were collected at 293 K, Siemens P4/V diffractometer, Mo,, radiation ( A = 0.71073 A), graphite monochromator. The structures were solved by direct methods (SHELXTL PLUS, PC version). (Non-hydrogen atoms anisotropic, H atoms in calculated positions and included in the refinement using the riding model U , , H -1.2 U., c). 4b: orange-yellow plates, C,,H,,P,S, M , = 366.4. triclinic, space group Pi: u = 9.343(4), b = 10.791(5),
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