Year: 2026
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide 3- C -Methyl- d -mannopyranose is a rare branched sugar whose derivatives also serve as precursors to the more common d -evalose (6-deoxy-3- C -methyl- d -mannose) and, after esterification at O3, as probes for the study of the mechanism of the stereodirecting effect of esters at the 3-position in mannopyranosylation reactions. We describe alternative syntheses of 4,6- O -benzylidene-protected 3- C -methylmannopyranosyl donors and their 3- O -benzoates and an interesting, reversible migration of a 2- O -silyl derivative on the attempted esterification at O3. We also describe the reversal of stereoselectivity on application of the Corey–Chaykovsky reaction to a 3-keto sugar based on a 4,6- O -benzylidene-protected α-mannopyranoside: the trimethylsulfonium iodide-derived ylid favored axial attack leading to the desired mannoisomer, whereas the more bulky trimethylsulfoxonium iodide-derived ylid gave the altro isomer of the resulting spiroepoxide as a consequence of preferential equatorial attack.
Source: ACS Omega
Authors: Shuay Abdullayev, Vikram A. Sarpe, David Crich
Institution: University of Georgia
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,935
OpenAlex ID: W7130510434