Nucleophilic Aromatic Substitution at Benzene with Powerful Strontium Hydride and Alkyl Complexes

Abstract

Abstract Key to the isolation of the first alkyl strontium complex was the synthesis of a strontium hydride complex that is stable towards ligand exchange reactions. This goal was achieved by using the super bulky β‐diketiminate ligand DIPeP BDI (CH[C(Me)N‐DIPeP] 2 , DIPeP=2,6‐di iso pentylphenyl). Reaction of DIPeP BDI‐H with Sr[N(SiMe 3 ) 2 ] 2 gave ( DIPeP BDI)SrN(SiMe 3 ) 2 , which was converted with PhSiH 3 into [( DIPeP BDI)SrH] 2 . Dissolved in C 6 D 6 , the strontium hydride complex is stable up to 70 °C. At 60 °C, H–D isotope exchange gave full conversion into [( DIPeP BDI)SrD] 2 and C 6 D 5 H. Since H–D exchange with D 2 is facile, the strontium hydride complex served as a catalyst for the deuteration of C 6 H 6 by D 2 . Reaction of [( DIPeP BDI)SrH] 2 with ethylene gave [( DIPeP BDI)SrEt] 2 . The high reactivity of this alkyl strontium complex is demonstrated by facile ethylene polymerization and nucleophilic aromatic substitution with C 6 D 6 , giving alkylated aromatic products and [( DIPeP BDI)SrD] 2 .