Conformation-Guided Remote C-H Functionalization of Aromatic Compounds

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Site-selective C-H functionalization at remote aromatic positions is challenging.
• Existing methods often lack control over selectivity, especially in complex polyaromatic systems.

Purpose of the Study:

• To develop a conformational control strategy for remote meta-selective C-H borylation.
• To enable selective functionalization of mono- and 1,2-disubstituted (poly)arenes.

Main Methods:

• Utilizing arene π-complexation with a chromium tricarbonyl (Cr(CO)3) tripod.
• Employing a tailored iridium catalyst with 2-aminophenanthroline ligands.
• Conducting computational studies using Density Functional Theory (DFT).

Main Results:

• Achieved remote meta-selective C-H borylation of arenes.
• The chromium tripod directs conformation, exposing the meta-C-H bond.
• The iridium catalyst overrides intrinsic substrate bias and enhances selectivity.
• Demonstrated site- and ring-selectivity in polyaromatics, surpassing nondirected methods.

Conclusions:

• The developed strategy offers a powerful approach for site-selective C-H functionalization.
• Cooperative effects between arene π-complexation and catalyst design are crucial for selectivity.
• This method provides access to previously challenging functionalization patterns.