Iodonium ion-assisted glycosylation of alkyl (aryl) 1-thio-glycosides: regulation of stereoselectivity and reactivity
✍ Scribed by Helene M. Zuurmond; Susanne C. van der Laan; Gijs A. van der Marel; Jacques H. van Boom
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- English
- Weight
- 233 KB
- Volume
- 215
- Category
- Article
- ISSN
- 0008-6215
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✦ Synopsis
Recent studies from this laboratory revealed' that iodonium ion-mediated glycosylations of suitably protected alkyl I-thioglycosides showed great promise for the synthesis of antigenic oligosaccharides'. In evaluating the scope of this glycosylation method, we now report a stereoselective and high-yielding approach toward the synthesis of an appropriately protected 1,2-c&linked disaccharide (i.e., 8) which is a key intermediate in the preparation of the tetrasaccharide hapten
from the glycopeptidolipid antigen of Mycobacterium aviztm serotype 4.
An effective route to 8 has to allow the stereoselective formation of a 1,2-cis linkage and extension at C-l and C-4' with L-talose and L-rhamnose units, respec:tively.