Zinc-Mediated Hydroxyallylation of Aldehydes with Cyclopropanols: Direct Access to Vicinal -,-Diols via Enolized Homoenolates.

Direct and diastereoselective synthesis of vicinal -,-diols has been achieved by zinc-mediated α-hydroxyallylation of aldehydes with cyclopropanols. The reaction features the action of the zinc-enolized homoenolate as a γ-oxyallyl nucleophile toward the carbonyl electrophile. The diastereoselectivity of the present reaction is ascribed to the strong preference for a chelated ()-configuration of the enolized homoenolate as well as the bicyclic chairlike transition state it forms with the aldehyde, where the aldehyde substituent prefers to occupy the pseudoaxial position.