摘要:
In the course of formation of a bisisopropylidene protective group by keeping D-xylose in a mixture Me2CO-(MeO)(2)CMe2-H2SO4 alongside the expected 1,2:4,5-O-diisopropylidene derivative formed minor dimethylacetal, 2,3:4,5-O-diisopropylidene-D-xylose, inseparable from the main product by the chromatography on SiO2. The conditions were found for the selective formation and isolation of the latter, some its one-pot transformations were studied resulting in synthetically promising orthogonally protected acyclic C-5-synthons.