Alkylalanes and methyl furanosides: regioselective O-debenzylation or acetal cleavage
摘要:
Perbenzylated methyl pentofuranosides were submitted to the action of three alkylalanes and regioselective debenzylation at O-2 of the four pentoses was observed when choosing the right match between anomeric configuration and aluminium reagent. Diisobutylalane (DIBAL-H) allowed an easy access to reduced open-chain compounds, whereas trimethylalane (TMAL) stereoselectively produced methylated open chain derivatives. (c) 2006 Elsevier Ltd. All rights reserved.
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