title: Synthesis of a disaccharide repeating unit of the O-antigen from Burkholderia ambifaria and its oligomers.
abstract: A disaccharide repeating unit of the O-antigen from Burkholderia ambifaria, 6-deoxy-β-d-Alt-(1 → 4)-α-d-Rha-O(CH2)3NH2(1), and its dimer and trimer, 6-deoxy-β-d-Alt-(1 → 4)-α-d-Rha-(1 → 3)-6-deoxy-β-d-Alt-(1 → 4)-α-d-Rha-O(CH2)3NH2(2) and 6-deoxy-β-d-Alt-(1 → 4)-α-d-Rha-(1 → 3)-6-deoxy-β-d-Alt-(1 → 4)-α-d-Rha-(1 → 3)-6-deoxy-β-d-Alt-(1 → 4)-α-d-Rha-O(CH2)3NH2(3), were synthesized via a convergent strategy. The key disaccharyl thioglycoside 4 as a glycosyl donor was stereoselectively assembled by glycosylation of rhammnosyl acceptor 5 with 6-deoxy-altrosyl trichloroacetimidate donor 6b. The glycosidation of 4 with 3-azidopropanol followed by global deprotection afforded the target disaccharide 1. Further elongation of the carbohydrate chain of this glycosidation product with the disaccharyl donor 4 followed by global deprotection generated rapidly the dimeric tetrasaccharide 2 and the trimeric hexasaccharide 3 in a convergent [2 + 2] and [2 + 2 + 2] manner, respectively.
authors.affiliation: National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Jinan 250010, PR China.
authors.forename: Dongyue
authors.initials: D
authors.lastname: Wang
authors.affiliation: National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Jinan 250010, PR China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Zhuge
authors.affiliation: Department of Chemistry, University of Florida, 214 Leigh Hall, Gainesville 32611, FL, United States.
authors.forename: Zhongwu
authors.initials: Z
authors.lastname: Guo
authors.affiliation: National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Jinan 250010, PR China. Electronic address: guofenggu@sdu.edu.cn.
authors.forename: Guofeng
authors.initials: G
authors.lastname: Gu
mesh_terms: D019117:Burkholderia / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000138:chemical synthesis* / Q000737:chemistry*; D019081:O Antigens / Q000737:chemistry*
chemical_list: D004187:Disaccharides; D019081:O Antigens
keywords: Burkholderia ambifaria; Carbohydrate vaccine; Lipopolysaccharide; O-Antigen; Synthesis