Designing Homogeneous Bromine Redox Catalysis for Selective Aliphatic C-H Bond Functionalization

Area of Science:

• Organic Chemistry
• Catalysis
• Photochemistry

Background:

• Homogeneous oxidation catalysis with bromine is underexplored.
• Selective functionalization of C(sp3)-H bonds remains a challenge.

Purpose of the Study:

• To explore homogeneous oxidation catalysis using bromine.
• To develop a selective method for C(sp3)-H bond oxidation and amination.
• To establish a novel synthesis for N-sulfonyl oxaziridines.

Main Methods:

• Photochemical initiation using visible light.
• Utilizing tetraalkylammonium bromide and meta-chloroperbenzoic acid as a catalyst system.
• Isolation of N-halogenated intermediates.

Main Results:

• Demonstrated convenient and selective oxidation of saturated C(sp3)-H bonds.
• Achieved remote, intramolecular, position-selective C-H amination in 20 examples.
• Isolated an N-halogenated intermediate as the active species in a Hofmann-Löffler reaction.
• Developed a one-pot synthesis for 15 N-sulfonyl oxaziridines from N-sulfonamides.

Conclusions:

• The developed system offers a new paradigm in molecular catalysis with bromine.
• This work provides efficient methods for C-H functionalization and oxaziridine synthesis.