Au → M bonds promote catalytic alkyne hydrofunctionalisation.
M Alexander Eltester1, Hans Gildenast1, Kristína Rabatinová1
1Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, Aachen D-52074, Germany. Michael.Tauchert@ac.rwth-aachen.de.
Chemical Communications (Cambridge, England)
|April 18, 2023
Summary
This study explores how metal ligands influence gold-catalyzed alkyne hydrofunctionalization reactions. The gold-zinc complex demonstrates exceptional performance as a catalyst for alkyne hydroamination, highlighting novel gold-metal interactions.
Area of Science:
- Organometallic Chemistry
- Catalysis
- Gold Chemistry
Background:
- Gold catalysis is crucial for various organic transformations, including alkyne hydrofunctionalization.
- Understanding the role of ancillary ligands, particularly metalloligands, is key to optimizing gold catalysts.
- The stabilization of gold species and modulation of Lewis acidity by metalloligands remain areas of active investigation.
Purpose of the Study:
- To investigate the impact of ambiphilic PMP-type metalloligands (M = CuI, AgI, ZnII) on gold-catalyzed alkyne hydrofunctionalization.
- To explore the nature of the Au → M bonds, including novel AuI → ZnII interactions.
- To evaluate the catalytic activity of these gold-metalloligand complexes in alkyne cycloisomerization and hydroamination reactions.
Main Methods:
- Synthesis and characterization of gold complexes featuring PMP-type metalloligands.
- Spectroscopic and structural analyses to confirm Au → M bonding.
- Catalytic testing of the synthesized complexes in propargylamide cycloisomerization and alkyne hydroamination.
Main Results:
- Ambiphilic PMP-type ligands successfully stabilize gold, forming Au → M bonds with CuI, AgI, and ZnII.
- Unprecedented AuI → ZnII interactions were observed and characterized.
- The Lewis acidity of gold increases with the metal in the order CuI < AgI < ZnII, correlating with catalytic activity.
- The Au/Zn complex (8) exhibits excellent catalytic efficiency for alkyne hydroamination and promotes the cycloisomerization of propargylamide (14).
Conclusions:
- Metalloligands significantly influence the electronic properties and catalytic behavior of gold complexes.
- The AuI → ZnII interaction is a key factor in enhancing Lewis acidity and catalytic performance.
- Gold/zinc complexes are highly effective catalysts for alkyne hydroamination, offering a promising route for synthetic applications.
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