A recyclable heavy fluorous tag carrying an allyl alcohol pendant group: design and evaluation toward applications in synthetic carbohydrate chemistry

作者：Fukuda Kazuo; Tojino Mami; Goto Kohtaro; Dohi Hirofumi; Nishida Yoshihiro; Mizuno Mamoru^*

来源：Carbohydrate Research, 2015, 407: 122-130.

DOI：10.1016/j.carres.2015.02.002

• Heavy fluorous tag
• Olefin cross metathesis
• Pd-catalyzed redox-relay
• Fluorous liquid-liquid extraction
• Glycosylation

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)-CH=CH-CH2-OH, 3 (n=1) or 4 (n=3)] by means of olefin cross metathesis. They were then subjected to beta-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 beta-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-beta-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.

• 出版日期2015-4-30