Organophosphorus Intermediates.IX. The Cleavage of α,ω-Bisdiphenylphosphinoalkanes with Lithium. A 31P N.M.R. Study

Article abstract of DOI:10.1071/CH9871341

The title phosphines, Ph2P(CH2)nPPh2 (n=2-5), react with lithium in tetrahydrofuran to give the corresponding 1, n-dilithio-1, n-di(phenylphosphines) directly with little or on intermediacy of the 1-lithio-1-phenyl-n-diphenylphosphinoalkanes which can, however, be obtained by arylation of the diphosphides.Methylenebisdiphenylphosphine and 1,4-diphenyl-1,4-diphosphinane undergo exclusive phosphorus-alkyl carbon cleavage.The chemistry and 31P n.m.r. spectroscopy of the diphosphides are described and the mechanism o the cleavage reaction is discussed.Some cleavage reactions in liquid ammonia are described.