Katalysierte Acetal‐Reduktion mit ‐Boranen – 1‐O‐Alkyl(aryl)alditole, Anhydroalditole und 1‐O‐Alditylalditole aus O‐Glycopyranosiden

Abstract

Die Umwandlung von Glycosiden und Disacchariden in Alditol‐Derivate gelingt mit Ethyldiboranen (6) in Gegenwart von 9‐Methansulfonyloxy‐9‐borabicyclo[3.31]nonan. Beispielsweise läßt sich das Per‐O‐diethylboryl‐D‐galactosid 1, R=BEt2, Xα=H, Xβ=OPh, zum 1‐O‐Phenyl‐D‐galactitol‐Derivat 2, R=BEt2, reduzieren; die Schutz gruppen können abgespalten werden.

Amphiphilic carbohydrate‐based mesogens, V. Mesogenic 1‐O‐alkyl‐D‐glucitols from alkyl D‐glucopyranosides

“…2a-e, which are used as starting compounds in the reductions, have not been further characterised and were immediately reduced with tetraethyldiborane(6) by heating to 120°C for 4 h in the presence of 0.1 equivalent of MSBBN, i.e. under standard conditions which have previously been used to achieve other glycoside hydroborations 13,14).…”