A concise formal stereoselective total synthesis of(-)-swainsonine

摘要

A short formal stereoselective synthesis of(-)-swainsonine(1) is described.Our synthesis started with the versatile building block(R)-3-benzyloxyglutarimide 5.Through controlled regioselective reduction,Ley's-sulfone chemistry(N-α-sulfonylation and ZnCl_2-catalyzed N-α-amidovinylation),an RCM reaction,and an amide reduction,the synthesis of unsaturated indolizidine(8R,8aS)-3 has been achieved in five steps.The indolizidine(8R,8aS)-3 is an advanced intermediate toward the synthesis of(-)-swainsonine(1).