A recyclable heavy fluorous tag carrying an allyl alcohol pendant group: design and evaluation toward applications in synthetic carbohydrate chemistry. (30th April 2015)

• Record Type: Journal Article
• Authors: Fukuda, Kazuo; Tojino, Mami; Goto, Kohtaro; Dohi, Hirofumi; Nishida, Yoshihiro; Mizuno, Mamoru
• Is Part Of: Carbohydrate research. Volume 407(2015)
• Page Start: 122
• Page End: 130
• Publication Date: 2015-04-30
• Subjects: Heavy fluorous tag -- Olefin cross metathesis -- Pd-catalyzed redox-relay -- Fluorous liquid–liquid extraction -- Glycosylation; Carbohydrates -- Periodicals; Chemistry, Organic -- Periodicals; Biochemistry -- Periodicals; Carbohydrates -- Periodicals; Chimie organique -- Périodiques; Glucides -- Périodiques; Biochemistry; Carbohydrates; Chemistry, Organic; Periodicals; Electronic journals; 507.78
• DOI: 10.1016/j.carres.2015.02.002
• Languages: English
• ISSNs: 0008-6215

Abstract

Abstract: Toward applications in synthetic carbohydrate chemistry, we converted our previous acid-resistant heavy fluorous tag [(Rf)3 C–CH2 –OH, 1 ] to allyl alcohol derivatives [(Rf)3 C–CH2 –O–(CH2 ) n –CHCH–CH2 –OH, 3 ( n =1) or4 ( 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 in3 and4 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 tag1 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 in4 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 of3 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 compound1 is applied as a recyclable tag in synthetic carbohydrate chemistry. Graphical abstract: Highlights: Novel heavy fluorous tags carrying an allyl alcohol group were designed and synthesized. The tagged glycoside suited to a series of chemical modification and glycosylation. Upon treatment with Pd(PPh3 )4, the sugar moiety could be released from the tag. With the Pd-catalyzed releasing reaction, the original tag can be recovered.