Bis-halo N,N-bisdimethylsilylmethylacetamides as dynamic probes for the effect of coordination on reactivity at silicon

Abstract

A series of bis-halo N,N-bisdimethylsilylmethylacetamides 1 has been designed and used to investigate the effect of coordination on reactivity at silicon; pentacoordinated SiCl and SiBr bonds are thermodynamically activated towards nucleophilic substitution by N-methylimidazole (NMI) and hexamethylphosphoramide (HMPA), by contrast coordination of R₃SiF renders the SiF bond less prone to substitution by nucieophiles than that in the tetracoordinated R₃SiF.