Direct photochemical cross-coupling between aliphatic acids and BF₃K salts

Area of Science:

• Organic Chemistry
• Photocatalysis
• Radical Chemistry

Background:

• Carbon-carbon bond formation is fundamental in organic synthesis.
• Developing selective methods for C(sp3)-C(sp3) bond construction remains a challenge.
• Photoredox catalysis offers a powerful platform for radical generation and transformations.

Purpose of the Study:

• To develop a novel photoredox hetero-coupling reaction for C(sp3) radicals.
• To achieve cross-selectivity in radical coupling based on kinetic differences.
• To enable the construction of sterically hindered C(sp3)-C(sp3) bonds.

Main Methods:

• Utilized an organic photoredox catalyst and an oxidant.
• Employed visible light irradiation for radical generation.
• Reacted aliphatic acids or their corresponding BF3K salts as radical precursors.

Main Results:

• Successfully demonstrated a novel photoredox hetero-coupling reaction.
• Achieved cross-selectivity in the coupling of two distinct C(sp3) radicals.
• Showcased broad substrate scope, including sterically demanding examples.
• Constructed challenging sterically hindered C(sp3)-C(sp3) bonds.

Conclusions:

• The developed method provides a versatile approach for C(sp3) radical hetero-coupling.
• Kinetic differences in radical persistence are key to achieving cross-selectivity.
• This visible-light-mediated reaction expands the toolkit for synthesizing complex organic molecules.