Asymmetric Synthesis of cis-2-Aminocyclopropanols by Intramolecular Mannich Addition of Silyloxy Benzyl Carbanions

An efficient, highly diastereoselective method for the preparation of protected cis-2-aminocyclopropanols from N-tert-butanesulfinyl ketimines and various aryl acylsilanes is described. A tandem process for carbon-carbon bond formation via nucleophilic addition to acylsilanes, Brook rearrangement, and intramolecular Mannich reaction has been developed.