Approach to the eleutherobin core: Synthesis of a key intermediate by intramolecular Diels-Alder cycloaddition

摘要

An attractive intermediate in the total synthesis of the eleutherobin core has been obtained. Both syn and anti aldol diastereoisomers were synthesized by two different diastereoselective reaction sequences from 5-methyl-4-(pyrrolydin-1'-yl)-5H-furan-2-one. Each diastereoisomer was esterified and subjected to an intramolecular Diels-Alder reaction, which led to an intermediate that possesses rings A and C of the eleutherobin skeleton.