Phosphanyl Ureas as Ligands for Ethylene Oligomerization: A Cascade Reaction

Abstract

The phosphanyl urea ligands MeNHC(O)NMePR ₂ ( 1 : R = Ph and 2 : R = 2,4-tBu ₂ C ₆ H ₃ O) form effective ethylene oligomerization catalysts with [Ni(cod) ₂ ] (cod = 1,5 cyclooctadiene). Whereas the primary product with 1 is butene, 2 initiates a cascade reaction leading to hexenes and octenes. In the first reaction cycle ethylene is dimerized to butene, which serves as feedstock for the second dimerization cycle to the final products hexenes and octenes.

Keywords:

• Cascade reaction
• ethylene oligomerization
• homogenous catalysis
• nickel
• phosphino urea
• phosphino amine
• transition metal

Acknowledgments

We thank Prof J. Heinicke, for his ongoing support and the use of his laboratory facilities.