Olefin hydroaryloxylation catalyzed by pincer-iridium complexes

Area of Science:

• Organometallic Chemistry
• Catalysis
• Organic Synthesis

Background:

• Aryl alkyl ethers are vital industrial chemicals, commonly synthesized via Williamson ether synthesis.
• Olefin hydroaryloxylation presents a more atom-economical alternative but suffers from poor selectivity with acidic catalysts.
• Existing transition-metal catalysts often rely on undesirable Brønsted acid pathways.

Purpose of the Study:

• To develop a highly selective and atom-economical method for synthesizing aryl alkyl ethers.
• To explore the use of iridium pincer complexes as catalysts for intermolecular hydroaryloxylation.
• To elucidate the catalytic mechanism, differentiating it from known acidic pathways.

Main Methods:

• Utilized iridium pincer complexes for the organometallic-catalyzed intermolecular hydroaryloxylation of unactivated olefins.
• Investigated reaction pathways, distinguishing from Brønsted acid catalysis.
• Characterized reaction intermediates and products.

Main Results:

• Achieved highly chemo- and regioselective synthesis of aryl alkyl ethers.
• Demonstrated that the iridium catalysts do not operate via a hidden Brønsted acid pathway.
• Proposed a mechanism involving olefin insertion into an iridium-alkoxide bond followed by C-H reductive elimination.

Conclusions:

• Organometallic catalysis with iridium pincer complexes offers a novel route to atom-economical ether synthesis.
• This method provides a selective alternative to traditional Williamson ether synthesis.
• The findings open avenues for synthesizing diverse oxygenates.