29 Si chemical shifts and additivity in pertrimethylsilylated O ‐methyl, O ‐benzyl, O ‐benzoyl and O ‐acetyl methyl β‐ D ‐xylopyranosides
1983; Wiley; Volume: 21; Issue: 11 Linguagem: Inglês
10.1002/omr.1270211105
ISSN0030-4921
AutoresJan Schraml, Eva Petráková, O. Pihar, Ján Hirsch, V. Chvalovský,
Tópico(s)Synthesis of Organic Compounds
ResumoAbstract 29 Si chemical shifts in pertrimethylsilylated O ‐methyl, O ‐benzoyl, O ‐benzoyl and O ‐acetyl methyl β‐ D ‐xylopyranoside derivatives are reported. The chemical shifts in monotrimethylsilyl derivatives with the same O ‐substituents are in the order: δ(Si‐2) > δ(Si‐4) > δ(Si‐3). When the chemical shifts in bis (trimethylsilyl) and tris(trimethylsilyl) derivatives are assigned according to this rule, all the chemical shifts agree well with a direct additivity rule. The only significant deviation from additivity occurs for methyl 2,4‐di‐ O ‐benzoyl‐3‐ O ‐trimethylsilyl‐β‐ D ‐xylopyranoside, which has a different average conformation from the other compounds studied.
Referência(s)