Synthesis of Benzene Derivatives with Multiple Dichlorophosphino Groups

The chlorination of 1,2‐diphosphinobenzene with PCl5 to 1,2‐bis(dichlorophosphino)benzene was performed with high yields (93 %) despite the high number of P−H functions. The method was further applied to other phosphanes, enabling the first synthesis and complete characterization of 1,2,4‐tris(dichlorophosphino)benzene (89 % yield) and 1,2,4,5‐tetrakis(dichlorophosphino)benzene (91 % yield), valuable precursors for example for binuclear complexes, coordination polymers, organic wires, or metal–organic frameworks. The application of the chlorophosphanes in base induced ring closure reactions with primary amines is demonstrated. The synthesis of benzene derivatives with multiple PCl2 groups, starting from the corresponding phosphanes by chlorination with PCl5 is reported in this work. The synthesised 1,2‐bis(dichlorophosphino)benzene, 1,2,4‐tris(dichlorophosphino)benzene and 1,2,4,5‐tetrakis(dichlorophosphino)benzene were isolated in excellent yields ≥89 %. The follow up chemistry towards primary amines is also described.