The Quest for Twofold Reductive P–C Bond Cleavage of P– Ph Substituted 1,4‐Dihydro‐1,4‐diphosphinine Derivatives

It is demonstrated that backbone chloro(phenyl)phosphanyl‐substituted imidazole‐2‐thiones 3 ( N‐ R = Me, Et, n Bu) can be easily synthesized which allow for a selective access to tricyclic 1,4‐diphenyl‐1,4‐dihydro‐1,4‐diphosphinines 5 via reaction with LDA. Furthermore, new examples for preferred substitution reactions are provided that occurred when KHMDS was used thus yielding P– N(SiMe 3 ) 2 substituted derivatives 4 . The new P– Ph substituted tricyclic 1,4‐dihydro‐1,4‐diphosphinine derivatives 5 were successfully employed to generate tricyclic bis‐phosphanides 6 using potassium in THF, and the formation of 6 was proven via quenching with excess of n ‐butyl iodide to give P–n Bu substituted derivatives 7 obtained as mixture of cis and trans isomers.