title: The first total synthesis of cytopiloyne, an anti-diabetic, polyacetylenic glucoside.
abstract: The first total synthesis of cytopiloyne 1, a novel bioactive polyacetylenic glucoside isolated from the extract of Bidens pilosa, is described. The structure of cytopiloyne was determined to be 2-β-D-glucopyranosyloxy-1-hydroxytrideca-5,7,9,11-tetrayne by using various spectroscopic methods, but the chirality of the polyyne moiety was unknown. Herein, the convergent synthesis of two diastereomers of cytopiloyne by starting from commercially available 4-(2-hydroxyethyl)-2,2-dimethyl-1,3-diozolane is described. The synthetic sequence involved two key steps: stereoselective glycosylation of the glucosyl trichloroacetimidate with 1-[(4-methoxybenzyl)oxy]hex-5-yn-2-ol to give the desired β-glycoside and the construction of the glucosyl tetrayne skeleton by using a palladium/silver-catalyzed cross-coupling reaction to form the alkyne-alkyne bond, the first such use of this reaction. Comparison between the observed and published characterization data showed the 2R isomer to be the natural product cytopiloyne.
authors.affiliation: Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, 35, Keyan Road, Zhunan Town, Miaoli County 35053, Taiwan, ROC.
authors.forename: Chidambaram Ramesh
authors.initials: CR
authors.lastname: Kumar
authors.forename: Chi-Hui
authors.initials: CH
authors.lastname: Tsai
authors.forename: Yu-Sheng
authors.initials: YS
authors.lastname: Chao
authors.forename: Jinq-Chyi
authors.initials: JC
authors.lastname: Lee
mesh_terms: D031176:Bidens / Q000737:chemistry; D002384:Catalysis; D005960:Glucosides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D006031:Glycosylation; D007004:Hypoglycemic Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D015394:Molecular Structure; D053279:Polyynes / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D013237:Stereoisomerism
chemical_list: D005960:Glucosides; D007004:Hypoglycemic Agents; C520271:cytopiloyne; D053279:Polyynes