Competitive Generation of CH and CSi Bonds by Reductive Elimination: Formation of Silametallacycles by Metalation of Silyl Ligands

Exclusive reductive elimination of methane occurs from the iridium complexes 1 and 2 on heating. This leads to the formation of new five-membered silametallacycles by metalation at the δ position of an OEt substituent and to new four-membered silametallacycles by orthometalation, respectively; in contrast, complex 3 eliminates both methane and Et3MeSi in a competitive reaction. The question whether CH or CSi elimination takes place in catalytic processes such as hydrosilation is thus also dependent on the nature of the substituents on the silyl ligand. LPMe3.