title: A recyclable heavy fluorous tag carrying an allyl alcohol pendant group: design and evaluation toward applications in synthetic carbohydrate chemistry.
abstract: Toward applications in synthetic carbohydrate chemistry, we converted our previous acid-resistant heavy fluorous tag [(Rf)3C-CH2-OH, 1] to allyl alcohol derivatives [(Rf)3C-CH2-O-(CH2)n-CH=CH-CH2-OH, 3 (n=1) or 4 (n=3)] by means of olefin cross metathesis. They were then subjected to β-glycosylation reactions by using a series of glycosyl donors, including glycosyl bromide and trichloroacetimidates. The terminal OH group in 3 and 4 was found to be β-glycosylated in moderate yield when 2,3,4,6-tetra-O-benzoyl-D-galactosyl trichloroacetimidate was used as the glycosyl donor. Upon a detachment reaction using Pd(PPh3)4, the initial heavy fluorous tag 1 was recovered in high yield (>90%) together with 1-hydroxy sugar, indicating that not only the allyl ether linkage in the glycosides but also the internal di-alkyl ether linkage in 4 be cleaved by the action of the Pd-catalyst enabling long-range olefin transmigration. Potential utility was demonstrated by using the tetra-O-benzoyl-β-D-galactosylated derivative of 3 in a series of deprotection, protection and glycosylation reactions, which were conductible in high yields without using chromatographic purification process. These findings prompt us to propose a general scheme in which the acid-resistant heavy fluorous compound 1 is applied as a recyclable tag in synthetic carbohydrate chemistry.
authors.affiliation: Laboratory of Glyco-organic Chemistry, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo 173-0003, Japan; Department of Nanobiology, Graduate School of Advanced Integration Science, Chiba University, 648 Matsudo, Matsudo, Chiba 271-8510, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Fukuda
authors.affiliation: Laboratory of Glyco-organic Chemistry, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo 173-0003, Japan.
authors.forename: Mami
authors.initials: M
authors.lastname: Tojino
authors.affiliation: Laboratory of Glyco-organic Chemistry, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo 173-0003, Japan.
authors.forename: Kohtaro
authors.initials: K
authors.lastname: Goto
authors.affiliation: Department of Nanobiology, Graduate School of Advanced Integration Science, Chiba University, 648 Matsudo, Matsudo, Chiba 271-8510, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Dohi
authors.affiliation: Department of Nanobiology, Graduate School of Advanced Integration Science, Chiba University, 648 Matsudo, Matsudo, Chiba 271-8510, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Nishida
authors.affiliation: Laboratory of Glyco-organic Chemistry, The Noguchi Institute, 1-8-1 Kaga, Itabashi-ku, Tokyo 173-0003, Japan. Electronic address: mmizuno@noguchi.or.jp.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Mizuno
mesh_terms: D002236:Carbohydrate Conformation; D060326:Chemistry Techniques, Synthetic / Q000379:methods; D006027:Glycosides / Q000138:chemical synthesis* / Q000737:chemistry; D006031:Glycosylation; D020005:Propanols / Q000138:chemical synthesis*
chemical_list: D006027:Glycosides; D020005:Propanols; C006463:allyl alcohol
keywords: Fluorous liquid–liquid extraction; Glycosylation; Heavy fluorous tag; Olefin cross metathesis; Pd-catalyzed redox-relay