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Synthesis of a Borylated Ibuprofen Derivative Through Suzuki Cross-Coupling and Alkene Boracarboxylation Reactions
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A catalytic borylation/dehalogenation route to o-fluoro arylboronates
Chathurika R K Jayasundara1, Jason M Unold1, Jossian Oppenheimer
1†Department of Chemistry, Michigan State University, 578 South Shaw Lane, East Lansing, Michigan 48824, United States.
Organic Letters
|November 25, 2014
Summary
This study introduces a new method for synthesizing fluoroarenes using iridium-catalyzed borylation and palladium-catalyzed dehalogenation. The process efficiently creates ortho-fluorinated boronic esters, valuable building blocks in organic chemistry.
Area of Science:
- Organic Chemistry
- Catalysis
- Fluorine Chemistry
Background:
- Fluoroarenes are important motifs in pharmaceuticals and materials science.
- Directing borylation ortho to fluorine remains a synthetic challenge.
- Existing methods often lack selectivity or require harsh conditions.
Purpose of the Study:
- To develop a novel two-step sequence for the synthesis of fluoroarenes.
- To achieve regioselective borylation ortho to a fluorine substituent.
- To enable the preparation of valuable ortho-fluorinated boronic esters.
Main Methods:
- Utilized a two-step sequence involving iridium-catalyzed borylation followed by palladium-catalyzed dehalogenation.
- Employed a para-halogen substituent on the arene to direct Ir-catalyzed borylation to the ortho position.
- Achieved chemoselective dehalogenation using potassium fluoride (KF) activated polymethylhydrosiloxane (PMHS).
Main Results:
- Successfully synthesized fluoroarenes with boronic ester groups positioned ortho to fluorine.
- Demonstrated regiocontrol in the borylation step by strategic placement of a para-halogen.
- Showcased the efficiency and selectivity of the Pd-catalyzed dehalogenation using KF-activated PMHS.
Conclusions:
- The developed Ir/Pd-catalyzed sequence provides a robust method for synthesizing ortho-fluorinated boronic esters.
- This approach overcomes previous limitations in regioselective borylation adjacent to fluorine.
- The methodology offers a valuable tool for accessing complex fluorinated organic molecules.
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