CATALYSIS LETTERS, cilt.150, sa.9, ss.2566-2571, 2020 (SCI-Expanded)
The present work was undertaken to ascertain whether IL-metal salt catalyzed isopropylidenation of d-fructose yield desired acetonides. For the first time, an imidazole based ionic liquid compound accompanied with strontium chloride has been identified as a suitable dual catalyst system for the chemoselective O-isopropylidenation of d-fructose with acetone. In the present protocol, mainly the kinetically controlled less stable cyclic ketal 1,2;4,5-di-O-isopropylidene-beta-d-fructopyranose is formed as an initial product with satisfactory yield and without isomerization to the thermodynamically more stable cyclic ketal 2,3;4,5-di-O-isopropylidene-beta-d-fructopyranose. Therefore, this protocol is more advantageous compared to other mineral acid catalyzed protocols that require more sensitive reaction conditions.