PHOSPHINE-LIGANDS .2. BIDENTATE PHOSPHINES OF HETEROARENES - 4,6-BIS(DIPHENYLPHOSPHINO)DIBENZOFURAN AND 4,6-BIS(DIPHENYLPHOSPHINO)DIBENZOTHIOPHENE

Twofold lithiation of dibenzofuran (6) and dibenzothiophene (12) with n-butyllithium/N,N,N',N'-tetramethylethylenediamine (TMEDA) in n-hexane or n-pentane followed by the reaction with chlorodiphenylphosphine yielded the title compounds 4 and 5, respectively. The monophosphines 4-(diphenylphosphino)dibenzofuran (11) and 4-(diphenylphosphino)dibenzothiophene (15) were obtained analogously via the monolithium compounds 9 and 14 of the heteroarenes. In the case of dibenzofuran (6), it was shown that mono- and dilithiation is controlled by temperature.