OVERVIEW

The palladium catalyzed C-C bond forming reactions became a significant tool in modern synthetic chemistry (2010 Nobel Prize for Chemistry). Although the application of these chemical transformations are indispensable in both small-scale and process chemistry operations, they still suffer from many drawbacks:

  • Stability: The Pd(0) catalysts are typically sensitive to air and moisture, besides being pyrophoric.
  • High catalyst load: Due to the poor stability of the catalyst, the processes necessitate the a relatively high catalyst load.
  • High palladium contamination: The high catalyst load and the uncontrollable catalyst decomposition often lead to a separation problem: metal impurities (Palladium black) can be only removed from products with special - and expensive - metal scavengers.

As a solution to the above problems, our firm has developed a new, robust trifluoromethyl tagged palladium(0) catalyst. The SUPERSTABLE Pd(0) CATALYST has a unique thermal, moisture, air and light stability which allows for a reduced catalyst load and low palladium contamination.
 
 

TEST OF STABILITY

We tested the storage stability of the SUPERSTABLE Pd(0) CATALYST  under a controlled GLP environment (on air, temperature of 40 °C and humidity of 75%). After 20 months, no change of color was observed and also no detectable decomposition occurred according to the 1H-NMR, 19F-NMR and 31P-NMR. Instead of minutes or hours - as with previous palladium(0) catalysts - the SUPERSTABLE Pd(0) CATALYST can be stored for years exposed to air at room temperature without any detectable decomposition.

 

 

We performed two Suzuki model reactions in the mixture of MeOH-H2O (10:1) system at 110°C. After one hour, the conversions were complete and no palladium black formation occurred. In comparison, the analogous Pd(PPh3)4 resulted in a palladium black formation after a few minutes.


     

 

Publications:

 

A Robust and Efficient Catalyst Possessing an Electron-Deficient Ligand 

for the Palladium-Catalyzed Direct Arylation of Heteroarenes (European 
Journal of Organic Chemistry 2015, 1, 56–59)
Alexandra Jakab, Zoltán Dalicsek and Tibor Soós
DOI: 10.1002/ejoc.201402586

Superstable Palladium(0) Complex as an Air- and Thermostable Catalyst 
for Suzuki Coupling Reactions, (European Journal of Organic Chemistry 
2015, 1, 60–66)
Alexandra Jakab, Zoltán Dalicsek, Tamás Holczbauer, Andrea Hamza, Imre 
Pápai, Zoltán Finta, Géza Timári and Tibor Soós
DOI: 10.1002/ejoc.201403214

The Conversion of 4‑Anilinoquinazoline- and 
3‑Aryl-4-imino-3,4-dihydro-quinazoline-2-carbonitriles into
Benzo[4,5]imidazo[1,2‑c]quinazoline-6-carbonitriles via Oxidative and 
Nonoxidative C−N Couplings, (J. Org. Chem. 2015, 80, 8329−8340), 
Styliana I. Mirallai and Panayiotis A. Koutentis
DOI: 10.1021/acs.joc.5b01514