Reactivity, Selectivity, and Synthesis of 4‐C‐Silylated Glycosyl Donors and 4‐Deoxy Analogues

• Published in: Angewandte Chemie International Edition Vol. 60; no. 5; pp. 2689 - 2693
• Main Authors: Jæger Pedersen, Martin, Pedersen, Christian Marcus
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 01.02.2021; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Carbohydrates; Cellulose; Chemistry; Chemistry, Multidisciplinary; Glycosylation; levoglucosenone; Physical Sciences; Reactivity; Science & Technology; Selectivity; silylation; synthesis; selectivity; synthesis; OXIDATION; 1,2-SILYL-MIGRATIVE CYCLIZATION; ACID; glycosylation; ALPHA; BETA; silylation; CARBON BOND; VINYLSILANES BEARING; CHEMISTRY; ORGANOSILICON COMPOUNDS; levoglucosenone; CONFORMATIONAL PREFERENCE
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202009209

A method for introducing dimethylphenylsilyl at the 4‐position in carbohydrates has been developed. Two C‐silylated glycosyl donors were prepared via levoglucosenone, starting from cellulose. The glycosylation properties were studied using three glucoside acceptors, a 3‐OH, 4‐OH, and 6‐OH. Compared with the 4‐deoxy variant, it was found that the anomeric selectivity was influenced more by the C‐2 substituents orientation than the silyl in the 4‐position. In general, the reactivity of these donors was higher than the corresponding 4‐deoxy‐analogue, albeit a competition experiment showed that the introduction of a C−Si increases the relative reactivity by a modest factor of around two. Two 4‐C‐silylated glycosyl donors have been synthesized starting from cellulose. This new class of donors showed remarkably similar selectivity to and modestly more reactivity than their 4‐C‐deoxy analogue, allowing for very mild glycosylation reaction conditions and short reaction times.