Palladium-catalyzed one-pot diarylamine formation from nitroarenes and cyclohexanones

Area of Science:

• Organic Chemistry
• Catalysis
• Synthetic Methodology

Background:

• Diarylamines are crucial structural motifs in pharmaceuticals and materials science.
• Existing synthetic methods often require harsh conditions or stoichiometric reagents.
• Development of efficient and sustainable routes for diarylamine synthesis is highly desirable.

Purpose of the Study:

• To develop the first palladium-catalyzed diarylamine synthesis utilizing nitroarenes and cyclohexanone derivatives.
• To employ a 'borrowed hydrogen' strategy for a cascade reaction.
• To achieve selective diarylamine formation with high yields and functional group tolerance.

Main Methods:

• Palladium-catalyzed cross-coupling reaction.
• Utilized nitroarenes and cyclohexanone derivatives as starting materials.
• Employed a cascade process involving nitro reduction, cyclohexanone dehydrogenation, and imine formation/reduction.

Main Results:

• Successfully synthesized various diarylamines with good to excellent yields.
• Demonstrated high selectivity in the diarylamine formation.
• The reaction cascade proceeded efficiently without the need for external reducing agents or oxidants, showcasing a 'borrowed hydrogen' mechanism.

Conclusions:

• A novel and efficient palladium-catalyzed protocol for diarylamine synthesis has been established.
• The method offers a sustainable and atom-economical approach by avoiding external reagents.
• This methodology provides a versatile platform for accessing diverse diarylamine structures.