Heterocyclic Tridentate Ligands for Effective Alkyne Metathesis

Area of Science:

• Organic Chemistry
• Catalysis
• Materials Science

Background:

• Tripodal ligands are crucial for developing efficient catalysts.
• Alkyne metathesis is a powerful tool for organic synthesis.
• Developing selective and robust catalysts remains a key challenge.

Purpose of the Study:

• To synthesize and screen a library of tripodal ligands based on a tris(biphenyl)methane scaffold.
• To identify an optimal ligand for alkyne metathesis reactions.
• To evaluate the catalyst's performance and substrate scope.

Main Methods:

• Suzuki reactions were employed to construct a library of 29 diverse tripodal ligands.
• Ligand screening was performed using the homometathesis of 4-nitrophenylpropylene.
• The optimal ligand (CP227) was used with precatalyst cat-III for in situ catalyst generation.

Main Results:

• Pyridine ligand CP227 was identified as the optimal ligand.
• The CP227-based catalyst demonstrated high efficiency in chloroform (CHCl3), replacing toxic carbon tetrachloride (CCl4).
• The catalyst exhibited compatibility with a wide range of functional groups and was used for macrocycle synthesis via ring-closing alkyne metathesis.

Conclusions:

• Tridentate ligands offer tunable catalytic performance for alkyne metathesis.
• CP227 represents a promising ligand for developing safer and more effective alkyne metathesis catalysts.
• This work expands the utility of alkyne metathesis in complex molecule synthesis.