A Facile Access to Trisaccharides with Central β-D-Mannose, α-D-Glucosamine, and β-D-Mannosamine Units

✍ Scribed by Lichtenthaler, Frieder W. ;Kaji, Eisuke

• Book ID: 102901430
• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: English
• Weight: 650 KB
• Volume: 1985
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.198519850811

✦ Synopsis

Abstract

An expedient synthesis of the trisaccharides β‐D‐Gal__p__‐(1→4)‐β‐D‐Man__p__‐(1→6)‐D‐Gal (8), β‐D‐Gal__p__‐(1→4)‐β‐D‐Man__p__NAc‐(1→6)‐D‐Gal (11), and β‐D‐Gal__p__‐(1→4)‐α‐D‐Glc__p__‐NAc‐(1→6)‐D‐Gal (12) is achieved utilizing the readily accessible lactose‐derived building blocks hexa‐O‐benzoyl‐α‐D‐lactosulosyl bromide (4) and its 2‐(benzoyloxy)imino analogue 5 as glycosyl donors and 1,2:3,4‐di‐O‐isopropylidene‐D‐galactose (6) as the acceptor. Stereocontrolled α‐ (silver triflate) and β‐glycosidations (silver carbonate) were as smoothly effected as the subsequent, essentially stereospecific reductions of oxo (NaBH~4~) and (benzoyloxy)‐imino functions (diborane). The overall yields of 55– 60% attainable for 4 → 8 and 5 → 11/12 render this disaccharide‐derived building block approach highly effective for the construction of oligosaccharides with interior β‐D‐Man, β‐D‐ManNAc, and α‐D‐GlcNAc units.