A stereoselective glycosidation using thioglycosides, activation by combination of N-bromosuccinimide and strong acid salts
1995; Elsevier BV; Volume: 51; Issue: 17 Linguagem: Inglês
10.1016/0040-4020(95)98690-j
ISSN1464-5416
AutoresKoichi Fukase, Atsushi Hasuoka, I. Kinoshita, Yutaka Aoki, Shoichi Kusumoto,
Tópico(s)Glycosylation and Glycoproteins Research
ResumoA stereoselective glycosidation with thioglycosides was effected under mild and neutral conditions by combined use of N-bromosuccinimide (NBS) and a catalytic amount of various strong acid salts. A combination of NBS with Ph2IOTf, Bu4NOTf, or Bu4NClO4 was advantageous for β-selective glucosidation with 2-O-acylated or 2-O-benzylated donors by virtue of either the neighboring group participation or the known solvent effect of nitrile, respectively. α-Selective glucosidation was effected by the use of a 2-O-benzylated donor in the presence of LiClO4 or LiNO3 as a catalyst in ether. Addition of silica gel to the reaction mixture increased both the α-selectivity and reaction rate.
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