Oxidative [4 + 2] annulation of 1-naphthols with alkynes accelerated by an electron-deficient rhodium(III) catalysts.

The 1,3-diethoxycarbonyl-2,4,5-trimethylcyclopentadienyl (Cp E ) rhodium(III) complex displayed high efficacy in the catalytic oxidative annulation of 1-naphthols with internal alkynes under mild conditions. DFT calculations revealed that lower activation energies for the concerted metalation-deprotonation and the reductive elimination steps are the key to improved reactivity.