Aryl(dimethylaminomethyl)phosphinic Acid Esters: Syntheses, Structures, and Reactions with Halogen Hydrogen Acids, Tin Halides, and Trimethyl Halosilanes

Abstract

This paper reports the synthesis of the aryl(iodomethyl)phosphinic acid ethyl esters, Ar(ICH2)P(O)OEt (Ar = Ph, Ar = mesityl), which, via dimethyamination, are converted to the corresponding aryl(dimethylaminomethyl)phosphinic acid ethyl esters, Ar(Me2NCH2)P(O)OEt (Ar = Ph, Ar = mesityl). Upon reaction with hydrogen chloride, compound Me2NCH2(Ph)P(O)OEt forms its hydrochloride salt as a crystalline material. Depending on the reaction conditions, treatment of Me2NCH2(Ph)P(O)OEt with SnCl2 gave either [Me2HNCH2(Ph)P(O)OEt][SnCl3] or the mixed‐valent dinuclear tin salt [{Me2HNCH2(Ph)P(O)O}4SnCl2][SnCl3]2, as its dichloromethane solvate. The reaction of Me2NCH2(Mes)P(O)OEt with SiMe3I gives the diorgano bis(trimethylsiloxy)phosphinium iodide [Me2NCH2(Mes)P(OSiMe3)2]I, as its toluene solvate. In solution, it is involved in an equilibrium with Me2NCH2(Mes)P(O)OSiMe3 and SiMe3I. From the hydrolysis of [Me2NCH2(Mes)P(OSiMe3)2]I, the hydrogen iodide derivative [Me2HNCH2(Mes)P(O)OH]I was obtained as three different solvates. [Me2NCH2(Mes)P(OSiMe3)2]I reacted with SnF2 to give a product mixture from which the mixed‐valent tin compound [{SnII2Me2NCH2(Mes)P(O)2}4SnIVF2]I2, was isolated. The compounds were characterized by NMR and IR spectroscopy, electrospray ionization mass spectrometry, and single‐crystal X‐ray diffraction analysis.