Electro-Oxidative C-C Alkenylation by Rhodium(III) Catalysis

Area of Science:

• Organometallic Chemistry
• Electrochemistry
• Synthetic Organic Chemistry

Background:

• Traditional C-C bond formation often relies on stoichiometric oxidants.
• Developing sustainable and selective methods for C-C bond activation is crucial in organic synthesis.
• Rhodium(III) catalysis offers a powerful platform for C-H and C-C functionalizations.

Purpose of the Study:

• To develop an electrochemical method for C-C activation using rhodium(III) catalysis.
• To achieve oxidative C-C alkenylations that avoid toxic transition-metal oxidants.
• To enable the synthesis of densely substituted arenes with high chemo- and regioselectivity.

Main Methods:

• Employing oxidative rhodium(III) catalysis in an electrochemical setting.
• Utilizing chelation assistance to direct C-C functionalization.
• Conducting mechanistic studies to elucidate the reaction pathway.

Main Results:

• Successful oxidative C-C alkenylations were achieved using electricity, replacing traditional oxidants.
• The reaction demonstrated broad substrate scope with excellent chemo- and regioselectivity.
• A catalytically competent rhodium(III) intermediate was identified, supporting a C-C scission mechanism.
• Gram-scale synthesis was feasible without additional electrolytes.

Conclusions:

• Electrochemical rhodium(III) catalysis provides an efficient and sustainable route for C-C activation.
• This method offers unique access to 1,2,3-substituted arenes, complementary to C-H activation strategies.
• The developed protocol is scalable and avoids hazardous reagents, highlighting its practical utility.