1-Hydroxysugars were dehydratively coupled with a variety of alcohols including thiophenol in the presence of a catalytic amount of ytterbium(III) triflate [Yb(OTf) 3 ] and methoxyacetic acid to give the corresponding glycosides in good to excellent yields, and in some cases, with high stereoselectivities. The reaction proceeds through selective esterification of 1-hydroxysugars with methoxyacetic
Stereoselective Synthesis of 1-Thio-α-<scp>d</scp>
-Ribofuranosides Using Ribofuranosyl Iodides as Glycosyl Donors
作者:Natsuhisa Oka、Ayumi Mori、Kaori Ando
DOI:10.1002/ejoc.201801201
日期:2018.12.6
A method for the 1,2‐cis‐selective synthesis of 1‐thio‐α‐ribofuranosides has been presented. Ribofuranosyl iodides as glycosyl donors react effectively with thiols under mild basic conditions to afford various 1‐thio‐α‐ribofuranosides, including some that are unstable under acidic conditions.
Study of the Endocyclic versus Exocyclic C–O Bond Cleavage Pathways of α- and β-Methyl Furanosides
作者:Olivier St-Jean、Michel Prévost、Yvan Guindon
DOI:10.1021/jo3027438
日期:2013.4.5
scaffolds (ribo, lyxo, arabino, and xylo) efficiently afforded acyclic thioacetals with high SN2-like selectivity at the acetal center in the presence of Me2BBr and thiophenol. The stereochemical outcome of these reactions provides important mechanisticinsights into the activation pathway of five-membered semicyclic acetals. The thioacetal products should find applications in oligosaccharides synthesis and
A phosphine/Cu(II) complex catalyzes the dehydrative glycosylation of tri-O-benzylated 1-hydroxyribofuranose to give the ribofuranoside with high stereoselectivity. (C) 2003 Elsevier Science Ltd. All rights reserved.