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We report on our initial results from a systematic effort to implement electron-withdrawing protecting groups and Lewis basic solvents/additives as an approach to 1,2- cis (α)-selective O -glucosylation. 1,2- cis -Selective O -glucosylations are reported with thioglucosides and glucosyl trichloroacetimidates and a range of acceptors. A correlation between electron-withdrawing effects and 1,2- cis selectivity has been established. This phenomenon may prove to be broadly applicable in the area of chemical O -glycosylation.
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This content will become publicly available on November 21, 2025
On the relevance of glycosyl oxonium ions to 1,2- cis -selective O -glycosylation in ether solvents
Since no later than the 1970s, organic chemists have speculated on the role of glycosyl oxonium ions in chemical O-glycosylation. Such species result from the attack of ethers on glycosyl oxocarbenium ions and are invoked to explain 1,2-cis-selectivity in ether solvents. However, a systematic study to probe this phenomenon appears to be lacking in the chemical literature. Herein, we study the effects of solvent, counteranion, protecting group electron-withdrawing effects, and acceptor on O-glycosylation stereoselectivity with D-glucosyl trichloroacetimidate donors. While many of these transformations proceed with 1,2- cis-selectivity, our results suggest that glycosyl oxonium ions play minimal, if any, role in O-glycosylation.
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- Award ID(s):
- 2101153
- PAR ID:
- 10621276
- Publisher / Repository:
- Taylor & Francis
- Date Published:
- Journal Name:
- Journal of Carbohydrate Chemistry
- Volume:
- 43
- Issue:
- 7-9
- ISSN:
- 0732-8303
- Page Range / eLocation ID:
- 302 to 322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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