Enantiopure Phospha[1]ferrocenophanes: Textbook Examples of Through‐Space Nuclear Spin–Spin Coupling

Three enantiopure phospha[1]ferrocenophanes (2R) equipped with either a phenyl, an isopropyl, or a tert‐butyl group at the bridging phosphorus atom were synthesized by a salt‐metathesis approach in isolated yields between 52 and 63 %. The chirality in these strained sandwich compounds stems from the planar‐chiral ferrocene moiety, which is symmetrically equipped with two iPr groups adjacent to phosphorus. Surprisingly, all three phospha[1]ferrocenophanes show an uncommon through‐space nuclear 1H–31P coupling. As a result of the embedded symmetry, these new compounds are ideal examples to differentiate between through‐space and through‐bond coupling mechanisms in NMR spectroscopy.