Synthesis of N,P-Disecondary o-Arylphosphanylanilines via o-(RNHC6H4P)-N-1(R)O2Et Precursors and Preliminary Study of Cyclocondensations with (EtO)(3)CH/NH4PF6

N-Secondary o-aminophenylarylphosphinates were prepared by Pd-catalyzed cross coupling of aryl-P(OEt)(2) with the corresponding o-bromoanilines and reduced with LiAlH4 to o-phosphanylanilines. For the N-mesityl compounds a two-step reduction was necessary because of competing P-N condensation reactions. Preliminary studies of cyclocondensations of o-(RPH)C6H4NHR1 with (EtO)(3)CH/NH4PF6 showed that, in contrast to benzimidazolium salts, accessible in this way from disecondary o-phenylenediamines, the homologous 1,3-benzazaphospholium salts are highly reactive and undergo instantaneous oxidative addition of EtOH, liberated in the condensation. The resulting 3-ethoxy-benzazaphospholinium salts, which for R = Ph, R-1 = Np are relatively stable and were detected by NMR and HRMS, decompose to yield P-oxo-1,3-benzazaphospholine center dot xHPF(6) salts, and for R-1 = Me additionally the rearranged N-ethyl-P-oxo-benzazaphospholinium salt. Detection of triethylphosphate indicates partial acid-catalyzed conversion of PF6- with EtOH. Alternative cyclocondensation of o-(MesPH)C6H4NHNp with excess Me2NCH(OMe)(2) in the presence of HCl/Et2O led to the 2-methoxy-, or after removal of MeOH under vacuum to the corresponding 2-dimethylamino-1,3-benzazaphospholine. The structure elucidation of the new compounds is based on multinuclear NMR data and confirmed for an o-anilinophenylphosphinate by crystal structure analysis.