α-Phosphino Amino Acids: Synthesis, Structure, and Reactivity of Phosphaprolines

Abstract

Linear phosphinoglycines proved sensitive to hydrolysis. Routes to heterocyclic α-phosphino amino acids were therefore investigated. The more stable phenylphosphaproline and some N- or C2-substituted derivatives thereof were synthesized from 2-phenylphosphino-ethylamines and α-ketocarboxylic acids. With Ni(COD)₂ they form greenish yellow complex solutions that in the presence of NaH generate ethylene oligomerization catalysts.

Keywords:

• Ethylene oligomerization
• hybrid ligands
• nickel catalysis
• phosphaprolines
• phosphino amino acids
• phosphorus heterocycles