Zur Reaktion von Dihydroxybiphenylen mit Phosphorpentachlorid - Phosphepine mit Phosphonium- und Phosphoranstruktur

The 2, 2'-dihydroxybiphenyl derivatives 1d-f react with phosphorus pentachloride to give the dioxaphosphepinium hexachlorophosphates 3a, 3b, and 17. The trichloro-dioxaphosphepins 8a, 8b, and 21 were discussed as intermediates, which were obtained by chlorination of the 6-chloro-dioxaphosphepins 7a, 7b, and 20. The hydrolysis of the dioxaphosphepins leads to the stable, cyclic phosphates 4a, 4b, 9a, 9b, 11a, 11b, 19a, and 19b. The crystal struc-ture of 4a was determined; two different molecules was observed in the asymmetric unit.