Iron-Based Catalyst for Borylation of Unactivated Alkyl Halides without Using Highly Basic Organometallic Reagents

Area of Science:

• Organic Chemistry
• Catalysis
• Organometallic Chemistry

Background:

• Borylation reactions are crucial for C-C bond formation.
• Developing mild and efficient borylation methods for alkyl halides remains a challenge.
• Iron catalysis offers a cost-effective and sustainable alternative to precious metal catalysts.

Purpose of the Study:

• To develop a novel, mild iron-catalyzed borylation of alkyl bromides and chlorides.
• To investigate the substrate scope and functional group compatibility of the developed method.
• To elucidate the reaction mechanism, including the role of the radical pathway.

Main Methods:

• Utilized bis(neopentylglycolato)diborane (B2neop2) as the boron source.
• Employed an iron-bis amide complex as the catalyst.
• Performed borylation on various primary and secondary alkyl halides.
• Conducted mechanistic studies to probe the reaction pathway.

Main Results:

• Achieved mild borylation of alkyl bromides and chlorides.
• Demonstrated broad substrate scope and good functional group compatibility.
• Obtained sufficient catalytic activity for primary and secondary alkyl halides.
• Identified a radical pathway for the borylation reaction.

Conclusions:

• The developed iron-catalyzed system provides an efficient method for alkyl halide borylation.
• The reaction's broad scope and functional group tolerance make it valuable for organic synthesis.
• Understanding the radical mechanism offers insights for further catalyst development.