Stereocontrolled Synthesis of Triols Containing Four Asymmetric Centers: Application of C, O-Chelated Germyl Enolates to a Diastereoselective Aldol Reaction.

The treatment of α,β-unsaturated ketones with divalent germanium salts cleanly generated C, O-chelated germyl enolates. The aldol reactions of the chelated enolates with the aldehydes achieved a high diastereoselectivity in the construction of the five-membered aldol adducts. Furthermore, the subsequent transformation of the Ge-C bond in the aldol adduct enabled the stereocontrolled synthesis of triols bearing four asymmetric centers.