Nitrones as directing groups in transition metal-catalysed C-H activation.

Area of Science:

• Organic Chemistry
• Catalysis
• Medicinal Chemistry

Background:

• Nitrones have gained prominence as directing groups in transition metal-catalyzed C-H activation over the past 15 years.
• Their utility extends beyond simple aryl ring functionalization to roles as transient directing groups or internal oxidants.

Purpose of the Study:

• This review focuses on the diverse applications of nitrones in C-H activation reactions.
• It covers functionalization of the aryl ring, nitrone moiety roles, and cascade reactions.

Main Methods:

• Exploration of transition metal-catalyzed reactions, including Rh, Ru, Pd, and emerging Co catalysis.
• Discussion of reactions involving C-H activation followed by 1,3-dipolar cycloaddition.
• Inclusion of catalytic reactions of isoelectronic azomethine imines.

Main Results:

• Nitrones facilitate redox-neutral reactions and the synthesis of nitrogen-containing polycyclic scaffolds.
• C(sp2)-H functionalization of the aldonitrone moiety is also reviewed.
• Cobalt catalysis presents new avenues for nitrone functionalization.

Conclusions:

• Nitrones are powerful tools for constructing complex molecular architectures relevant to biologically active compounds.
• The review highlights the expanding scope of nitrone chemistry in catalysis and synthesis.