A Convenient Synthesis of 1‐Deoxy‐8a‐<i>epi</i>‐Castanospermine Diastereoisomers (6<i>R</i>,7<i>R</i>,8<i>S</i>,8a<i>S</i>)‐6,7,8‐Trihydroxyindolizidine and (6<i>R</i>,7<i>R</i>,8<i>R</i>,8a<i>S</i>)‐6,7,8‐Trihydroxyindolizidine

Abstract

Abstract An efficient synthesis of (6 R ,7 R ,8 S ,8a S )‐6,7,8‐trihydroxyindolizidine and (6 R ,7 R ,8 R ,8a S )‐6,7,8‐trihydroxyindolizidine is described from readily available N ‐BOC‐ L ‐proline, (BOC = tert ‐butoxycarbonyl) which involves the addition of ethyl lithiopropiolate to the aldehyde derived from N ‐BOC‐ L ‐proline as a key step, then cyclization to construct indolizidine skeletons and asymmetric dihydroxylation. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2003)