Bio-inspired synthesis of rare and unnatural carbohydrates and cyclitols through strain driven epimerization
作者:Raja Mohanrao、Aromal Asokan、Kana M. Sureshan
DOI:10.1039/c4cc00868e
日期:——
Bio-inspired isomerization of carbohydrates and cyclitols to their rare and unnatural isomers, through strain-driven epimerization of trans-ketals to cis-ketals, is introduced.
Zizyphus saponins I, II, III and jujuboside B were isolated from Zizyphi Fructus. On Smith-de Mayo degradation, zizyphus saponins I, II and III yielded jujubogenin as a genuine aglycone. The configuration of the sugar linkages in each saponin was determined on the basis of PMR and CMR examinations and application of Klyne's rule on molecular rotation, and the structures of zizyphus saponins I, II and III were established as (I), (II) and (III), respectively. 6-Deoxy-L-talose was isolated as a sugar component of zizyphus saponins I and III.