Amido derivatives of metals and metalloids. Part VIII. Metathetical reactions of organostannanes; their use in amination

Abstract

Aminostannanes are shown to be effective aminating agents for a wide variety of substrates, via a metathetical ligand-exchange reaction. Thus, fluorine can be substituted in hexafluorobenzene, chlorotrifluoroethylene, bistrifluoromethylamine, trifluoroborane–ether, trifluoro-phosphine, -arsine, and -stibine, and titanium tetrafluoride; and chlorine in trichloroborane, chlorotrimethylsilane, and molecular chlorine, by an amino-group with concomitant formation of the organotin halide. Similarly, hydrogen (attached to boron) is displaced from triethylamine–borane; and butyl, phenyl, and ethyl groups are displaced from tributylborane, triphenylborane, and triethylalane. Methoxy- and ethoxy-groups are displaced from trimethoxyborane, diphenylmethoxyborane, and some carboxylic esters; and acetate can also be replaced. Phosphinostannanes undergo similar reactions, as demonstrated by the exchange of diphenylphosphino- and butylthio-ligands.

It is suggested that these amination reactions owe their facility to the high donor strength of R₃SnNMe₂ and the weak and polar Sn–N bond. In the cases where pseudo-ionic products are formed, e.g., R₃SnF, the large values for their heats of formation are considered to be important.