Synthesis of diastereomerically pure indolizidine and pyrrolizidine analogues from D-pentoses

Article abstract of DOI:10.1016/S0957-4166(97)00427-8

Partially protected D-pentoses were stereoselectively transformed into the corresponding thiazolidines by the action of cysteamine. Then, a cyclisation with n-BuLi/TsCl or n-Bu₃P/DIAD led to indolizidine or pyrrolizidine analogues. Alternatively, a one-pot preparation of diastereomerically pure indolizidine analogues was realized from 5-O-tosyl-D-pentose derivatives and cysteamine.