ASYMMETRIC REDUCTIVE CYCLIZATION - TOTAL SYNTHESIS OF (-)-C-10-DESMETHYL ARTEANNUIN-B

An efficient total synthesis of (-)-C-10-desmethyl arteannuin B (5) ha s been achieved. The sequence features the use of a chiral auxiliary t o introduce absolute asymmetry at an early stage and a stereoselective , chelation-controlled reductive cyclization of 8, using samarium diio dide as the reducing agent. The methodology promises to be applicable to the synthesis of a wide range of analogs capable of being converted to potent antimalarial agents related to artemisinin (1).