Magnesium-Promoted Benzidine-Type Rearrangement for Regioselective Construction of Polyfunctionalized Biaryls

Area of Science:

• Organic Chemistry
• Synthetic Chemistry

Background:

• Benzidine-type rearrangements are crucial for synthesizing biaryl compounds.
• Existing methods often require harsh conditions or transition metals.

Purpose of the Study:

• To develop a novel, transition-metal-free method for synthesizing 1-amino-1-hydroxy-4,4-biaryls.
• To explore substrate control for regioselective benzidine-type rearrangements.

Main Methods:

• Magnesium-promoted benzidine-type rearrangement of 1,3-dihalonitroarenes.
• Utilized aryl Grignard reagents and specifically designed substrates with ortho and meta substituents.
• Investigated intramolecular cyclization of trifluoroacetamide-substituted nitroarenes.

Main Results:

• Achieved highly regioselective and efficient synthesis of 1-amino-1-hydroxy-4,4-biaryls.
• Demonstrated broad functional-group tolerance and excellent scalability.
• Successfully synthesized CF3-substituted benzimidazoles via a [5,5]-rearrangement and cyclization pathway.

Conclusions:

• Established a sustainable and mechanistically tunable strategy for biaryl and heteroaromatic synthesis.
• Expanded the scope of benzidine-type rearrangements with a novel magnesium-promoted approach.
• Provided direct access to polyfunctionalized biaryls and valuable heterocyclic compounds.