Dual Control of the Selectivity in the Formal Nucleophilic Substitution of Bromocyclopropanes en Route to Densely Functionalized, Chirally Rich Cyclopropyl Derivatives

Densely substituted cyclopropanol and cyclopropylazole derivatives with three stereogenic carbons in the small cycle are obtained via a highly diastereoselective formal nucleophilic substitution of bromocyclopropanes. The chiral center at C-2 in bromocyclopropane dictates the configuration of the other two stereocenters that are successively installed via a sterically controlled addition of a nucleophile, followed by a thermodynamically driven epimerization of the resulting enolate intermediate.