Glycosyl Phosphites as Glycosyl Donors – A Comparative Study

✍ Scribed by Müller, Thomas ;Hummel, Gerd ;Schmidt, Richard R.

• Book ID: 102366354
• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 468 KB
• Volume: 1994
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199419940403

✦ Synopsis

Abstract

Tri‐O‐benzyl‐L‐fucose (3) was transformed into the bis(trichloroethyl) phosphite derivative 4 which was allowed to react with 3‐O‐unprotected azidoglucose 7 as fucosyl acceptor in the presence of TMSOTf as catalyst to furnish disaccharide building block 1, useful in Lewis antigen X (Le^X^) synthesis, in 75% yield. Similarly, 2,3,4,6‐tetra‐O‐acetyl‐D‐galactose (8) was transformed into the bis(trichloroethyl) phosphite derivative 9 which afforded by treatment with acceptor 7 disaccharide 10 in 64% yield. The reaction of the derived acceptor 11 with donor 4 furnished trisaccharide building block 12, useful in Lewis antigen A (Le^a^) synthesis, in 88% yield. Transformation into the less reactive donor 14 and reaction with lactose acceptor 15 gave pentasaccharide 2 only in modest yield, thus exhibiting the scope and limitations of phosphite leaving groups in glycosylation reactions. magnified image