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

✍ Scribed by Koichi Fukase; Ikuko Kinoshita; Takeshi Kanoh; Yoshihiko Nakai; Atsushi Hasuoka; Shoichi Kusumoto

• Book ID: 104207310
• Publisher: Elsevier Science
• Year: 1996
• Tongue: French
• Weight: 472 KB
• Volume: 52
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(96)00057-9

✦ Synopsis

Combinations of iodosobenzene (PhlO) and various acids effectively promote glycosidafion using thioglycosides as glycosyl donors. 13-Selective glucosidation was effected by use of TfOH, Tf20, TMSOTf, Sn(OTf)2, and Yb(OTf) 3 as catalysts with 2-O-benzoylawxl or 2-0benzylated donors by virtue of either the neighboring group participation or the solvent effect of acetonitrile, respectively. Combinations of PhlO with SnCI2-AgCIO4, SnCI4-AgCIO4, BiCI3-AgC104, and SbCi3-AgCIO,I in ether were advantageous for a-glucosidation, where 2,2,2-trichloroethoxycarbonyl group introduced at the 6-position of a 2-O-benzylated donor remarkably increased aselectivity.