Optically active transition-metal complexes. Part 79. Optically active organoiron enantiomers formed by HF cleavage of the P–N bond in the aminophosphine ligand of separated diastereoisomers

Abstract

Liquid HF cleaves the P–N bond in [Fe(η-C₅H₅)(CO)I{P(C₆H₅)₂-N(CH₃)CH(CH₃)(C₆H₅)}](1), without attack at the Fe–I bond, to give quantitatively [Fe(ηC₅H₅)(CO)I{P(C₆H₅)₂F}](2). Using the aminophosphine with (S) configuration at the asymmetric carbon atom in the amino-component, (1) forms a pair of diastereoisomers. (+)₃₆₅ and (–)₃₆₅, which only differ in the configuration at iron. The HF cleavage can be used to convert the separated (+)₃₆₅ and (–)₃₆₅ diastereoisomers of (1) into the corresponding enantiomers of (2). Extensive racemisation with respect to the chiral Fe atoms during the HF reaction can be excluded.