کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1389059 | 982839 | 2011 | 11 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Glycosylation studies on conformationally restricted 3,5-O-(di-tert-butylsilylene)-d-galactofuranosyl trichloroacetimidate donors for 1,2-cis α-d-galactofuranosylation Glycosylation studies on conformationally restricted 3,5-O-(di-tert-butylsilylene)-d-galactofuranosyl trichloroacetimidate donors for 1,2-cis α-d-galactofuranosylation](/preview/png/1389059.png)
Conformationally restricted 3,5-O-di-tert-butylsilylene-d-galactofuranosyl trichloroacetimidate donors were synthesized from allyl α-d-galactofuranoside for the construction of 1,2-cis α-d-galactofuranosyl linkages. Glycosylation reactions were performed with several acceptors, including d-galactono-1,4-lactone, d-rhamnopyranosyl, and d-mannopyranosyl derivatives. The influence of the temperature and the reaction solvents was evaluated, as well as the 6-O-substitution pattern of the donor. The higher α-selectivities were obtained at −78 °C in diethyl ether as solvent. 6-O-Acetyl substitution on constrained donor increased the α-selectivity compared to the 6-O-benzyl substitution. Almost no selectivities were observed in the non-participating solvent CH2Cl2. In contrast, ethereal solvents enhanced the α-selectivity suggesting a participating effect in the reaction intermediate.
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Journal: Carbohydrate Research - Volume 346, Issue 18, 27 December 2011, Pages 2838–2848