Model studies towards the total synthesis of the Stemona alkaloid 1-hydroxyprotostemonine: synthesis of ent-1-hydroxystemoamide

As part of a model study towards the total synthesis of Stemona alkaloid 1-hydroxyprotostemonine 1, we have achieved the synthesis an A-B-C ring precursor, ent-1-hydroxystemoamide. Key steps involve an ene-yne RCM reaction and a diastereoselective dihydroxylation-lactonization reaction.