Photo-induced metal-free dehydrogenative N-N homo-coupling

Area of Science:

• Organic Chemistry
• Photochemistry
• Synthetic Methodology

Background:

• Nitrogen-nitrogen (N-N) bond formation is crucial in synthesizing various organic molecules.
• Existing methods for N-N coupling often require harsh conditions, expensive catalysts, or transition metals.
• Developing efficient and sustainable methods for N-N coupling remains an active area of research.

Purpose of the Study:

• To develop a novel, simple, and sustainable method for photo-induced dehydrogenative N-N coupling.
• To explore the scope of this reaction with different nitrogen-containing substrates.
• To investigate the preliminary mechanism of the photo-induced coupling reaction.

Main Methods:

• Utilizing readily available di-tert-butyl peroxide (DTBP) as a radical initiator.
• Employing visible light irradiation to trigger the reaction.
• Investigating the coupling of diarylimines, diarylamines, carbazoles, and anilines under metal- and catalyst-free conditions.

Main Results:

• Successful photo-induced dehydrogenative homo-coupling of diarylimines, diarylamines, carbazoles, and anilines was achieved.
• The reaction proceeds efficiently under mild, catalyst-free, and metal-free conditions.
• A good substrate scope was demonstrated for the developed protocol.
• Preliminary mechanistic studies suggest a pathway involving photo-induced homolytic cleavage of DTBP and subsequent hydrogen atom transfer, forming N-centered radicals.

Conclusions:

• A novel and operationally simple photo-induced N-N coupling method has been established.
• This metal- and catalyst-free protocol offers a sustainable alternative for synthesizing N-N coupled products.
• The reaction mechanism involves photoinitiated radical intermediates, providing insights into N-centered radical chemistry.