Reaktionen von unsymmetrischen λ 5 P – λ 3 P-Diphosphorverbindungen und von Diphosphinen (λ 3 P – λ 3 P) mit o-Chinonen / Reactions of Unsymmetrical λ 5 Ρ – λ 3 Ρ Diphosphorus Compounds and of Diphosphines (λ 3 P – λ 3 P) with o-Quinones

The reaction of λ 5 Ρ – λ 3 Ρ diphosphorus compounds with o-quinones, e.g. tetrachloro-o-benzoquinone or 2,5-di-tert-butyl-o-benzoquinone, led not only to oxidative addition of the o-quinone to λ 3 Ρ but also to insertion of a further molecule of o-quinone into the P–P bond (i.e. λ 5 Ρ – λ 3 Ρ diphosphorus compound and o-quinone reacted in a molar ratio 1:2). In the course of these oxidative addition and insertion reactions the o-quinones were converted into the corresponding hydroquinones (i.e. catechols). The products of these reactions were characterized by NMR and mass spectrometric methods, and by elemental analysis. The hydrolysis of the 1:2 addition products proceeded with cleavage of a P–O–C (hydroquinone) bond and formation of mononuclear products, involving λ 4 Ρ and λ 5 Ρ, respectively. A mechanism of this hydrolysis is proposed and has been elucidated by independent synthesis of some products. Diphosphines, i.e. symmetrical λ 3 Ρ – λ 3 Ρ diphosphorus compounds, were found to react with o-quinones in the same fashion in a molar ratio 1:3, i.e. with oxidative addition of the o-quinone to both λ 3 P atoms and insertion of tetrachloro-o-catechol into the P–P bond.