Synthesis of Functionalized (η⁵ -Indenyl)rhodium(III) Complexes and Their Application to C-H Bond Functionalization

It has been established that reductive complexation of functionalized benzofulvenes, which are readily prepared from commercially available indene and 2-methylindene, with RhCl₃ in ethanol affords the corresponding indenyl-rhodium(III) dichlorides bearing substituents at the 1- (H or CO₂ Et), 2- (H or Me), and 3- [CH₂ Ph or CH₂ (2-MeOC₆ H₄ )] positions. The indenyl-rhodium(III) complexes bearing one ethoxycarbonyl group showed higher thermal stability and regioselectivity than our previously reported Cp^E Rh^III complex toward the oxidative [3+2] annulation of acetanilides with internal alkynes.