A New Cysteine-Derived Ligand as Catalyst for the Addition of Diethylzinc to Aldehydes: The Importance of a ‘Free’ Sulfide Site for Enantioselectivity - Braga, Antonio L; Alves, Elenilson F; Silveira, Claudio C; Zeni, Gilson; Appelt, Helmoz R; Wessjohann, Ludger A (Synthesis, 2005)