Desymmetrization of spiro-activated meso-cyclopropanes via nucleophilic substitution

The spiro-activated cyclopropane undergoes desymmetrization either with Li-thiophenoxide in the presence of a chiral complexing ligand, or with ion pairs formed from thiophenols and aromatic chiral amines. The latter procedure is more efficient and provides the ring-opened thioether in up to 79% yield and up to 60% ee.