Site-Selective Acylation of Pyranosides with Oligopeptide Catalysts

作者：Alexander Seitz, Raffael C. Wende, Emily K. Roesner, Dominik Niedek, Christopher Topp, Avene C. Colgan, Eoghan M. McGarrigle, Peter R. Schreiner · 发表于：The Journal of Organic Chemistry · 年份：2021 · DOI：10.1021/acs.joc.0c02772 · 被引用次数：12 · 研究领域：Carbohydrate Chemistry and Synthesis、Glycosylation and Glycoproteins Research、Chemical Synthesis and Analysis

Herein, we report the oligopeptide-catalyzed site-selective acylation of partially protected monosaccharides. We identified catalysts that invert site-selectivity compared to N -methylimidazole, which was used to determine the intrinsic reactivity, for 4,6- O -protected glucopyranosides ( trans -diols) as well as 4,6- O -protected mannopyranosides ( cis -diols). The reaction yields up to 81% of the inherently unfavored 2- O -acetylated products with selectivities up to 15:1 using mild reaction conditions. We also determined the influence of protecting groups on the reaction and demonstrate that our protocol is suitable for one-pot reactions with multiple consecutive protection steps.