Asymmetric Reductive Cyclization. Total Synthesis of (−)-C10-Desmethyl Arteannuin B

An efficient total synthesis of (−)-C 10 -desmethyl arteannuin B ( 5 ) has been achieved. The sequence features the use of a chiral auxiliary to introduce absolute asymmetry at an early stage and a stereoselective, chelation-controlled reductive cyclization of 8, using samarium diiodide 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 ).