A New Synthesis of P‐Substituted 2,3‐Dihydro‐1,3‐dimethyl‐1,3,2δ3‐benzodiazaphosphorin‐4(1H)‐ones and Alkylaminodifluorophosphanes with Chlorodifluorophosphane. — Synthesis and Structure of {cis‐Bis[bis(2‐chloroethyl)aminodifluorophosphane]dichloro}platinum(II)

Abstract

Abstract2,3‐Dihydro‐1,3‐dimethyl‐2‐oxo‐1,3,2δ4‐benzodiazaphosphorin‐4(1H)‐one 1 reacted with diethylaminotrimethylsilane to give solely the 2‐trimethylsiloxy‐δ3‐diazaphosphorinone 2. The reaction of 2 with the 2‐chloro‐δ3‐diazaphosphorinone 3 yielded the P—O—P‐bridged compound 4 in an equilibrium reaction with elimination of trimethylchlorosilane. The synthesis of the P‐difluorophosphite‐substituted δ3‐benzodiaza‐phosphorinone 6 was effected by the reaction of chlorodifluorophosphane (5) with 1 in the presence of triethylamine in a 1:1 molar ratio, or in the reaction of 5 with 2 or 4. The reaction of 5 with 6 led, with elimination of μ‐oxo‐bis(difluoro‐phosphane), to the P(III)Cl species 3, 5 reacted with N,N'‐dimethylanthranilamide in the presence of triethylamine in a 2:1:2 molar ratio to give the N,N'‐bis(difluorophosphane) derivative 9, as evidenced by low temperature (‐30°C) 19F‐and 31P‐NMR data. At room temperature the 2‐fluoro‐δ3‐diazaphosphorinone 10 was formed from 9 with intramolecular elimination of phosphorus trifluoride. 2‐Chloroethyl‐ or bis(2‐chloroethyl)aminodifluorophosphane 11 and 12 were obtained in the reaction of 5 with 2‐chloroethyl‐ or bis(2‐chloroethyl)amine hydrochloride in the presence of triethylamine in a 1:1:2 molar ratio. 12 reacted with (COD)PtCl2 (COD = 1,5‐cyclooctadiene) in a 2:1 molar ratio to give the {cis‐bis[bis(2‐chloroethyl)aminodifluorophosphane]dichloro}platinum(II) complex 13. The characterization of 2, 4, 6, and 11–13 is based on their NMR and mass spectra. The structures of 10 and 13 were established by single‐crystal X‐ray analysis. 10 crystallizes with two independent molecules. Both six‐membered heterocycles display an envelope conformation with the phosphorus atoms 36.9 and 50.4 pm, respectively, out of the plane. The phosphorus atoms have pyramidal coordination geometry. The cis‐configuration at platinum(II) in the complex 13 was confirmed; two ligands (12) are coordinated to PtII via phosphorus. The platinum atom has a distorted square‐planar coordination geometry.