ammonia in diethyl ether T=-50°C;

in toluene soln. of Me2Si(NtBu)2Sn added dropwise to a soln. of the silylamine in toluene, stirring for two hours, refluxed for one hour, volatile substances removed in vacuum, seconorcubane-like intermediate pyrolysed in vacuo at 0.01 Torr and 250°C; product sublimed, elem. anal.;