Stereoselective beta-mannosylations and beta-rhamnosylations from glycosyl hemiacetals mediated by lithium iodide

Pongener, Imlirenla; Pepe, Dionissia A.; Ruddy, Joseph J.; McGarrigle, Eoghan M.

Abstract

Stereoselective β-mannosylation is one of the most challenging problems in the synthesis of oligosaccharides. Herein, a highly selective synthesis of β-mannosides and β-rhamnosides from glycosyl hemi-acetals is reported, following a one-pot chlorination, iodination, glycosylation sequence employing cheap oxalyl chloride, phosphine oxide and LiI. The present protocol works excellently with a wide range of glycosyl acceptors and with armed glycosyl donors. The method doesn't require conformationally restricted donors or directing groups; it is proposed that the high β-selectivities observed are achieved via an SN2-type reaction of α-glycosyl iodide promoted by lithium iodide.

Citation

Pongener, I., Pepe, D. A., Ruddy, J. J., & McGarrigle, E. M. (2021). Stereoselective beta-mannosylations and beta-rhamnosylations from glycosyl hemiacetals mediated by lithium iodide. Chemical Science, 12(29), 10070-10075. https://doi.org/10.1039/d1sc01300a

• Journal Article Type: Article
• Acceptance Date: Jun 16, 2021
• Online Publication Date: Jul 5, 2021
• Publication Date: Aug 7, 2021
• Deposit Date: Jun 5, 2023
• Journal: CHEMICAL SCIENCE
• Print ISSN: 2041-6520
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 12
• Issue: 29
• Pages: 10070-10075
• DOI: https://doi.org/10.1039/d1sc01300a
• Public URL: https://keele-repository.worktribe.com/output/436606