Electrooxidative Ruthenium-Catalyzed C-H/O-H Annulation by Weak O-Coordination

Area of Science:

• Organometallic Chemistry
• Electrocatalysis
• Sustainable Chemistry

Background:

• Electrocatalysis is a powerful tool in organometallic catalysis.
• Current electrocatalytic C-H activation methods require strong N-coordinating directing groups.
• A need exists for broader substrate scope and milder reaction conditions.

Purpose of the Study:

• To present the first example of electrocatalytic C-H activation utilizing weak O-coordination.
• To enable electrooxidative C-H/O-H functionalization for alkyne annulations.
• To demonstrate the use of electricity as the sole oxidant, avoiding metal oxidants.

Main Methods:

• Development of a ruthenium(II) carboxylate catalyst.
• Electrochemical C-H/O-H functionalization reactions.
• Mechanistic studies including C-H ruthenation and electrochemical reoxidation.

Main Results:

• Successful electrocatalytic C-H activation via weak O-coordination.
• Versatile functionalization of alkynes achieved using sustainable electricity.
• Identification of a ruthenium(0) intermediate crucial for the catalytic cycle.

Conclusions:

• This work expands the scope of electrocatalytic C-H activation to weak O-directing groups.
• The developed method offers a sustainable and efficient alternative to traditional organometallic catalysis.
• The findings pave the way for greener synthetic methodologies in catalysis.