Synthetic studies toward a simplified eleuthoside core

A concise approach to a simplified eleuthoside core is described. This synthetic pathway takes advantage of an aldol motif strategically positioned to direct the course of key transformations by way of an in-situ retro-aldol process. This putative reaction manifold enables an intramolecular Diels–Alder reaction to establish the requisite A-ring framework and therein three contiguous chiral centers ( 4 ), a regioselective one-carbon homologation to complete the B-ring carbon skeleton and finally a fragmentation process that unveils the eunicellan scaffold ( 29 ), which was further functionalized to eleuthoside 37 . Graphical Abstract