Substrate-Controlled Selectivity Switch in the Three-Component Coupling Involving Arynes, Aromatic Tertiary Amines,...

Area of Science:

• Organic Chemistry
• Catalysis
• Green Chemistry

Background:

• Multicomponent reactions offer efficient synthetic routes.
• Transition-metal-free catalysis is desirable for sustainability and cost-effectiveness.
• Aryne chemistry provides a versatile platform for C-C and C-heteroatom bond formation.

Purpose of the Study:

• To develop a novel transition-metal-free multicomponent coupling reaction.
• To investigate the switchable selectivity of the reaction based on amine electronics.
• To explore new synthetic pathways for functionalized benzoates.

Main Methods:

• Utilizing arynes as key reactive intermediates.
• Employing aromatic tertiary amines with varying electronic properties.
• Reacting with carbon dioxide (CO2) as a C1 building block.
• Characterizing products using spectroscopic methods (e.g., NMR, Mass Spectrometry).

Main Results:

• The reaction successfully couples arynes, aromatic tertiary amines, and CO2 without transition metals.
• Switchable selectivity was observed: electron-rich/neutral amines yielded 2-arylamino benzoates (via N to O migration).
• Electron-deficient amines led to 2-aminoaryl benzoates (via aryl to aryl amino migration, resembling a Smiles rearrangement).

Conclusions:

• A novel and versatile transition-metal-free multicomponent reaction has been established.
• The electronic properties of aromatic amines dictate the reaction pathway and product formation.
• This methodology offers a sustainable and efficient approach to synthesize diverse benzoate derivatives.