Dehydrogenative silylation of alcohols catalysed by half-sandwich iron N-heterocyclic carbene complexes

Abstract

A new series of tetramethylcyclopentadienyl-functionalised N-heterocyclic carbene complexes of iron bearing different wingtips of general type (Cp*-NHCR)Fe(CO)I (R = nBu, iBu, Et, CH2CH2OMe, CH2Ph) were prepared by direct reaction of Fe3(CO)12 and the corresponding imidazolium proligands. These new iron-NHC complexes have been found to be efficient catalysts for the dehydrogenative silylation of alcohols with silanes. Iron metal complexes bearing iso-butyl and n-butyl wingtips displayed slightly better catalytic performances than the related complexes (Cp*-NHCR)Fe(CO)I (R = Et, CH2CH2OMe, CH2Ph), affording quantitative yields of the corresponding silylethers in 8 h at 70 °C in acetonitrile.