Asymmetric Total Synthesis of Eupalinilide E, a Promoter of Human HSPC Expansion

A concise and scalable asymmetric total synthesis of eupalinilde E from (R)-(-)-carvone in 12 steps is reported with an overall yield of 20%. The key steps of the synthesis are a tandem Favorskii rearrangement-elimination reaction in the chromatography-free synthesis of carvone-derived 2-cyclopentene carbaldehyde and its catalyst-free stereospecific tandem allylboration-lactonization using recyclable trifluoroethanol as a promoter and solvent affording β-hydroxymethyl-α-methylene-γ-butyrolactone.