Asymmetric Synthesis and Highly Diastereoselective ortho‐Lithiation of Ferrocenyl Sulfoxides. Application to the Synthesis of Ferrocenyl Derivatives with Planar Chirality

Enantiomerically pure sulfoxides with planar chirality (3, R = tBu, p-Tol, X = H) can be prepared by the asymmetric synthesis of sulfoxides 1, and subsequent diastereoselective deprotonation to give 2, X = H. Double deprotonation of 1, R = tBu, provided 2, X = Li, which could be converted into diphosphane 3, X = E = PPh2.