Chelation-assisted Rh^I-catalyzed ortho-alkylation of aromatic ketimines or ketones with olefins

Described herein is the Rh^I-catalyzed ortho-alkylation of aromatic ketimines or ketones with olefins. This method showed high reactivity and selectivity to monoalkylation for a variety of olefins including 1-alkenes with an allylic proton, a,w-dienes, and internal olefins. For a mechanistic study, H/D exchange experiments were carried out, which demonstrated that the ortho C-H bond could be easily cleaved even at the low temperature of 45°C. The key step of this reaction is the formation of a stable five-membered metallacycle by a chelation-assisted ortho C-H bond activation. Furthermore, the direct ortho-alkylation of aromatic ketones with the Rh^I complex was successfully achieved by adding 50 mol % of benzylamine as a chelation-assistant tool.