The Mechanism of Rhodium-Catalyzed Allylic C-H Amination

Herein, the mechanism of catalytic allylic C-H amination reactions promoted by Cp*Rh complexes is reported. Reaction kinetics experiments, stoichiometric studies, and DFT calculations demonstrate that the allylic C-H activation to generate a Cp*Rh(π-allyl) complex is viable under mild reaction conditions. The role of external oxidants in the catalytic cycle is elucidated. Quantum mechanical calculations, stoichiometric reactions, and cyclic voltammetry experiments concomitantly support an oxidatively induced reductive elimination process of the allyl fragment with an acetate ligand proceeding through a Rh(IV) intermediate. Stoichiometric oxidation and bulk electrolysis of the proposed π-allyl intermediate are also reported to support these analyses. Lastly, evidence supporting the amination of an allylic acetate intermediate is presented. We show that Cp*Rh(III)²⁺ behaves as a Lewis acid catalyst to complete the allylic amination reaction.

Allylic C–H functionalization via group 9 π-allyl intermediates

This perspective presents an analysis of how reagent choice impacts mechanism and regioselectivity in group 9-catalysed allylic C–H functionalization.

Intermolecular Allylic C-H Etherification of Internal Olefins

Herein we report on the development of an oxidative allylic C-H etherification reaction, utilizing internal olefins and alcohols as simple precursors. Key advances include the use of RhCp* complexes to promote the allylic C-H functionalization of internal olefins and the compatibility of the oxidative conditions with oxidatively sensitive alcohols, enabling the direct etherification reaction. Preliminary mechanistic studies, consistent with C-H functionalization as the rate determining step, are presented.