Different reaction routes found in acid-catalyzed glycosylation of endo- and exo-glycals: competition between Ferrier rearrangement and protonation
作者:Hui-Chang Lin、Wen-Ping Du、Chih-Chun Chang、Chun-Hung Lin
DOI:10.1016/j.tetlet.2005.05.061
日期:2005.7
products is often obtained resulting from Ferrier rearrangement and protonation. The former reaction exclusively takes place with the t-butyl carbonate or hydroxyl substituent at the C3 position of endo-glycals, while the latter mainly occurs in the glycosylation of exo-glycals with allyl benzyl ether or acetate. In addition to the substituenteffect, protecting groups are critical to determine the
Stereoselective glycosylation of d-galactals by diethyl phosphorochloridite- and AlCl3-assisted Ferrier rearrangement
作者:Yen-Bo Chen、Su-I. Wang、Zi-Ping Lin、Chun-Hung Lin、Min-Tsang Hsieh、Hui-Chang Lin
DOI:10.1016/j.tet.2014.11.027
日期:2015.1
α-2,3-Unsaturated galactosides were synthesized in good to excellent yields by the initial activation of d-galactals with diethyl phosphorochloridite and the subsequent glycosyl addition via Ferrier rearrangement with various O-nucleophiles in the presence of AlCl3. The two-step reactions were carried out in one-pot and finished within 60 min in 81–95% yield to give the glycoside products with excellent