Minimally CompetentLewisAcid Catalysts: Indium(III) and Bismuth(III) Salts Produce Rhamnosides (=6-Deoxymannosides) in High Yield and Purity
| Autor: | Tucker Carrocci, Clifford S. Coss, Robin Polt, Raina M. Maier, Jeanne E. Pemberton |
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| Rok vydání: | 2012 |
| Předmět: |
chemistry.chemical_classification
Glycosylation Organic Chemistry chemistry.chemical_element Glycoside Biochemistry Catalysis Bismuth Inorganic Chemistry chemistry.chemical_compound chemistry Yield (chemistry) Drug Discovery Organic chemistry Lewis acids and bases Physical and Theoretical Chemistry Indium |
| Zdroj: | Helvetica Chimica Acta. 95:2652-2659 |
| ISSN: | 0018-019X |
| Popis: | Glycosylation of decan-1-ol (2), (±)-decan-2-ol (3), and (±)-methyl 3-hydroxydecanoate (4) with L-rhamnose peracetate 5 to produce rhamnosides (=6-deoxymannosides) 6, 7, and 8 in the presence of Lewis acids BF3⋅Et2O, Sc(OTf)3, InBr3, and Bi(OTf)3 was studied (Table 1). While the strong Lewis acids BF3⋅Et2O and Sc(OTf)3 were effective as glycosylation promoters, they had to be used in excess; however, glycosylation required careful control of reaction times and temperatures, and these Lewis acids produced impurities in addition to the desired glycosides. Enantiomerically pure rhamnosides (R)-1 and (S)-1 (Fig.) were obtained from L-rhamnose peracetate 5 and (±)-benzyl 3-hydroxydecanoate (9) via the diastereoisomeric rhamnosides 10 (Table 2; Scheme 3). The much weaker Lewis acids InBr3 and Bi(OTfl)3 produced purer products in high yield under a wider range of conditions (higher temperatures), and were effective glycosylation promoters even when used catalytically ( |
| Databáze: | OpenAIRE |
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