α-Stereoselective 3-Deoxy-d- manno -oct-2-ulosonoic Acid (Kdo) O -Glycosylation with a p -Toluenethioglycoside Donor by the ( p -Tol) 2 SO/Tf 2 O Preactivation Strategy

• Published in: Organic letters Vol. 25; no. 22; pp. 4150 - 4155
• Main Authors: Zhang, Jing-Dong, Gao, Xiao-Jie, Liu, Si-Cong, Geng, Zhu-Feng, Chang, Le, Liu, Yi-Jiang, Ma, Qing-Yu, Xing, Guo-Wen, Liu, Guang-Jian, Fang, De-Cai
• Format: Journal Article
• Language: English
• Published: United States 09.06.2023
• Subjects: Cardiac Glycosides; Glycosides; Glycosylation; Lipopolysaccharides; Sugar Acids
• ISSN: 1523-7060; 1523-7052
• DOI: 10.1021/acs.orglett.3c01430

A convenient and efficient approach was developed to synthesize α-Kdo -glycosides based on the Tf O/( -Tol) SO preactivation strategy using peracetylated Kdo thioglycoside as a donor. Under the optimized reaction conditions, several -glycoside products, including α-(2 → 1)-, α-(2 → 2)-, α-(2 → 3)-, and α-(2 → 6)-Kdo products, were stereoselectively synthesized in high yields. Remarkably, a series of aromatic α-Kdo -glycosides were first and successfully constructed in high yields. An S 2-like mechanism was revealed by DFT calculations and experimental results.