Stereoselective Total Synthesis of (-)-(2S,4R)-3'-Methoxyl Citreochlorol: Preparation and Use of New Proline-Based Auxiliary for Asymmetric Acetate Aldol Reaction.

The first stereoselective total synthesis of (-)-(2S,4R)-3'-methoxy citreochlorol and (-)-(2S,4S)-3'-methoxy citreochlorol is demonstrated. A proline-based imidazolidinone was synthesized and used as chiral auxiliary for asymmetric acetate aldol reaction to generate initial chirality in the targeted molecule. Geminal dichloromethane functionality was introduced by the addition of in situ generated dichloromethyllithium to Weinreb's amide functional group.