Further studies in the chemistry of 2,3-dihydro-1,2,3-triphenyl-1H-1,2,3-benzotriphosphole and related compounds. Part I

Abstract

The study of the probable mechanisms whereby certain o-dihalogenobenzenes react with the crude product of the interaction of lithium and phenylphosphonous dichloride to form 2,3-dihydro-1,2,3-triphenyl-1H-1,2,3-benzo-triphosphole (I) and 5,10-dihydro-5,10-diphenylphosphanthren (II) has been extended. Lithium reacts with certain polyphenylcyclopolyphosphines in solution, giving a product (XIV) which similarly reacts with o-dihalogenobenzenes to form the benzotriphosphole (I). The latter can also be obtained by the interaction of phenylphosphonous dichloride and o-phenylenebis[lithio(phenyl)phosphine]. The syntheses of the 1,2,3-triethyl and 1,2,3-trimethyl analogues of compound (I) are described. The structures of their various P-sulphides have been elucidated by ³¹P n.m.r. spectroscopy; in particular the disulphides have been shown to have the sulphur linked to P-1 and P-3. The ¹H n.m.r. and mass spectra of various new compounds are discussed.