Template synthesis of 9-membered triphospha-macrocycles with rigid o-phenylene backbone functions

Abstract

[η⁵-Cp^RFe(CH₃CN)(1,2-diphosphinobenzene)]⁺ complexes are readily formed from [η⁵-Cp^RFeL₃]⁺ salts and act as template precursors for the intramolecular hydrophosphination of co-ordinated trivinylphosphine with 1,2-diphosphinobenzenes. This sequence constitutes a versatile synthetic route to a new class of co-ordinated triphosphacyclononanes bearing a rigid o-phenylene backbone link. The efficiency of the synthesis depends markedly upon the nature of the Cp^R ligand. The new secondary phosphine macrocycles prepared by this route are readily alkylated to tritertiary triphosphine macrocycles bearing alkyl and pendant functions.