A novel method for stereoselective glycosidation with thioglycosides: Promotion by hypervalent iodine reagents prepared from PhIO and various acids.

被引:63
作者
Fukase, K
Kinoshita, I
Kanoh, T
Nakai, Y
Hasuoka, A
Kusumoto, S
机构
[1] Department of Chemistry, Faculty of Science, Osaka University, Toyonaka
关键词
D O I
10.1016/S0040-4020(96)00057-9
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Combinations of iodosobenzene (PhIO) and various acids effectively promote glycosidation using thioglycosides as glycosyl donors. beta-Selective glucosidation was effected by use of TfOH, Tf(2)O, TMSOTf, Sn(OTf)(2), and Yb(OTf)(3) as catalysts with 2-O-benzoylated or 2-O-benzylated donors by virtue of either the neighboring group participation or the solvent effect of acetonitrile, respectively. Combinations of PhIO with SnCl2-AgClO4, SnCl4-AgClO4, BiCl3-AgClO4, and SbCl3-AgClO4 in ether were advantageous for alpha-glucosidation, where 2,2,2-trichloroethoxycarbonyl group introduced at the 6-position of a 2-O-benzylated donor remarkably increased alpha-selectivity.
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页码:3897 / 3904
页数:8
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