Disaccharide fluoride donor

Ley and coworkers reported the one-pot synthesis of tetrasaccharide 176 by combining selective activation with reactivity-based armed-disarmed glycosylation [113]. As shown in Scheme 6.35, the first chemoselective coupling was achieved via selective activation of the fluoride donor 173 over the selenoglycoside acceptor 174. The resulting disaccharide intermediate was more armed than the bifunctional... 

Nicolaou [47] has applied this methodology in synthetic studies towards the antibiotic everinomicin 13,384-1. Glycosylation of immobilized fluoride donors such as 258 (Scheme 65) with sugar acceptors allowed the synthesis of disaccharides such as 259, attached to solid support through a selenium fink-... 

To show the applicability of this strategy to the synthesis of longer-chain oligosaccharides, iterative couplings were further examined by constructing the hepta-saccharide 12 in which all synthons were derived from 1. Firstly, thioglycoside donor 7 was coupled with acceptor fluoride 3 under conditions (a) to give the disaccharide fluoride 8 (85%) which was then reacted with the acceptor 4 to produce 9... 

The a-(2- 8)-linked Kdo disaccharide thioglycoside donor 125 was elaborated by Baasov et al. via reaction of fluoride 123 with phenyl 2-thio-ketoside 124 to give disaccharide 125 in 65% yield, which was then attached to a tri-glucosamine acceptor 126 by NIS-promoted coupling in 45% yield (Scheme 20). Compound 127 was obtained as 1 1 anomeric mixture and converted to a deprotected pentasaccharide with GTPase activity. ... 

Trialkylsilane resin (PS-DES) 50 was incorporated for solid-phase glycosylation by anchoring a glycosyl donor via their corresponding thio-phenyl ether or 3-glucopyranosyl fluorides (Scheme 20) [59]. Disaccharides... 

---