title: Microwave-assisted one-pot synthesis of 1,6-anhydrosugars and orthogonally protected thioglycosides.
abstract: Living organisms employ glycans as recognition elements because of their large structural information density. Well-defined sugar structures are needed to fully understand and take advantage of glycan functions, but sufficient quantities of these compounds cannot be readily obtained from natural sources and have to be synthesized. Among the bottlenecks in the chemical synthesis of complex glycans is the preparation of suitably protected monosaccharide building blocks. Thus, easy, rapid, and efficient methods for building-block acquisition are desirable. Herein, we describe routes directly starting from the free sugars toward notable monosaccharide derivatives through microwave-assisted one-pot synthesis. The procedure followed the in situ generation of per-O-trimethylsilylated monosaccharide intermediates, which provided 1,6-anhydrosugars or thioglycosides upon treatment with either trimethylsilyl trifluoromethanesulfonate or trimethyl(4-methylphenylthio)silane and ZnI2, respectively, under microwave irradiation. We successfully extended the methodology to regioselective protecting group installation and manipulation toward a number of thioglucosides and the glycosylation of persilylated derivatives, all of which were conducted in a single vessel. These developed approaches open the possibility for generating arrays of suitably protected building blocks for oligosaccharide assembly in a short period with minimal number of purification stages.
authors.affiliation: Genomics Research Center, ‡Institute of Chemistry, and §Chemical Biology and Molecular Biophysics, Taiwan International Graduate Program, Academia Sinica , 128, Section 2, Academia Road, Taipei 115, Taiwan.
authors.forename: Yen-Chun
authors.initials: YC
authors.lastname: Ko
authors.forename: Cheng-Fang
authors.initials: CF
authors.lastname: Tsai
authors.forename: Cheng-Chung
authors.initials: CC
authors.lastname: Wang
authors.forename: Vijay M
authors.initials: VM
authors.lastname: Dhurandhare
authors.forename: Pu-Ling
authors.initials: PL
authors.lastname: Hu
authors.forename: Ting-Yang
authors.initials: TY
authors.lastname: Su
authors.forename: Larry S
authors.initials: LS
authors.lastname: Lico
authors.forename: Medel Manuel L
authors.initials: MM
authors.lastname: Zulueta
authors.forename: Shang-Cheng
authors.initials: SC
authors.lastname: Hung
mesh_terms: D002236:Carbohydrate Conformation; D008872:Microwaves; D009844:Oligosaccharides / Q000138:chemical synthesis* / Q000737:chemistry; D013865:Thioglycosides / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D009844:Oligosaccharides; D013865:Thioglycosides