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Ligand-Controlled Regioinduction in a PHOX-Ni Aryne Complex.
Alexander Umanzor1, Nicholas A Garcia1, Courtney C Roberts1
1Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States.
ACS Organic & Inorganic Au
|February 12, 2024
Summary
This study introduces the first phosphinooxazoline (PHOX) ligand-nickel aryne complex, demonstrating its ability to control regioselectivity in metal-catalyzed reactions. The findings highlight the ligand
Area of Science:
- Organometallic Chemistry
- Catalysis
- Ligand Design
Background:
- Phosphinooxazoline (PHOX) ligands are versatile tools for controlling selectivity in metal-catalyzed reactions.
- The application of PHOX ligands in metal-aryne complexes has not been previously explored.
Purpose of the Study:
- To report the first synthesis and characterization of a PHOX-Ni aryne complex.
- To investigate the regiochemical outcomes induced by the PHOX ligand in metal-aryne chemistry.
- To elucidate the structural and electronic properties of these novel complexes.
Main Methods:
- Synthesis of a novel phosphinooxazoline-nickel aryne complex.
- Spectroscopic techniques including UV/vis spectroscopy.
- Electrochemical analysis using cyclic voltammetry.
- Single-crystal X-ray crystallography for structural determination.
- Methylation/deuteration sequences to assess ligand influence on product distribution.
Main Results:
- Successful formation of the first PHOX-Ni aryne complex.
- Demonstration of PHOX ligand-induced regiocontrol, yielding an 81:19 mixture of ortho-methoxy substituted aryne complexes.
- Structural and electronic insights obtained through X-ray crystallography, UV/vis, and cyclic voltammetry.
- Retention of regiocontrol in difunctionalized products, attributed to the trans influence of the phosphorus donor.
Conclusions:
- Phosphinooxazoline ligands can effectively control regioselectivity in nickel-aryne complexes.
- The differentiated P and N donors, along with steric factors, are key to achieving regiocontrol.
- The trans influence of the phosphorus donor plays a critical role in the regiospecificity of difunctionalization reactions.
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