Hydrosilylation in Aryliminopyrrolide-Substituted Silanes

Abstract

A range of silanes was synthesized by the reaction of HSiCl3 with iminopyrrole derivatives in the presence of NEt3. In certain cases, intramolecular hydrosilylation converts the imine ligand into an amino substituent. This reaction is inhibited by factors such as electron-donating substitution on Si and steric bulk. The monosubstituted (DippIMP)SiHMeCl (DippIMP=2-[N-(2,6-diisopropylphenyl)iminomethyl]pyrrolide), is stable towards hydrosilylation, but slow hydrosilylation is observed for (DippIMP)SiHCl2. Reaction of two equivalents of DippIMPH with HSiCl3 results in the hydrosilylation product (DippAMP)(DippIMP)SiCl (DippAMP=2-[N-(2,6-diisopropylphenyl)aminomethylene]pyrrolide), but the trisubsitituted (DippIMP)3SiH is stable. Monitoring the hydrosilylation reaction of (DippIMP)SiHCl2 reveals a reactive pathway involving ligand redistribution reactions to form the disubstituted (DippAMP)(DippIMP)SiCl as an intermediate. The reaction is strongly accelerated in the presence of chloride anions.