MOP-phosphonites: A novel ligand class for asymmetric catalysis

Abstract

Chiral phosphonite ligands (S,R_b)-5a, (S,S_b)-5b, (R,R_b)-6a and (R,S_b)-6b are introduced, comprising a MOP-type backbone with a binol-based binaphthyl group bound to the phosphorus. Their reaction with [Pd(η³-C₄H₇)Cl]₂ affords η³-methallylpalladium chloride complexes 7a/b and 8a/b which have been isolated and structurally characterised. Solid-state and solution studies indicate subtle differences in their coordination behaviour, which ultimately affects their efficacy in the asymmetric hydrosilylation of styrene.