Synthetic Diversity from a Versatile and Radical Nitrating Reagent

Area of Science:

• Organic Chemistry
• Synthetic Methodology
• Radical Chemistry

Background:

• C-H functionalization is crucial for synthesizing complex organic molecules.
• Developing new reagents for selective C-H diversification remains a key challenge in organic synthesis.

Purpose of the Study:

• To introduce a novel succinimide-derived reagent for efficient C-H diversification of alkenes and alkynes.
• To explore the mechanistic pathway involving nitryl radical generation and its applications in organic synthesis.

Main Methods:

• Utilized a newly discovered succinimide-derived reagent for slow nitrogen dioxide liberation.
• Employed in situ photo-sensitized electron paramagnetic resonance spectroscopy with nitrone spin-trapping to detect radical intermediates.
• Investigated photoredox conditions for late-stage C-H diversification using the reagent.

Main Results:

• Achieved C-H diversification of alkenes and alkynes, yielding aryl β-nitroalkenes, β-nitrohydrins, and β-nitroethers.
• Mechanistic studies confirmed the generation of a nitryl radical via N-N bond fragmentation.
• Demonstrated the formation of isoxazolines and isoxazoles through 1,3-dipolar cycloaddition with in situ generated nitrile oxides.

Conclusions:

• The developed succinimide reagent offers a versatile and efficient platform for C-H diversification.
• The study provides direct evidence for nitryl radical participation in the reaction mechanism.
• The protocol is mild, regioselective, general, and exhibits broad chemoselectivity, making it valuable for synthetic applications.