Reductive Coupling and Loss of N-2 from Magnesium Diazomethane Derivatives

The reductive coupling of two diazomethanes is affected by reaction with [(NacNac(Mes))Mg](2) affording the species [(NacNac(Mes))Mg(N2CPh2)](2) 2 and [(NacNac(Mes))-Mg(N2C(C6H4)(2))](2) 3. These species containing N-4 linkages readily evolve the central N-2 at 50 and 75 degrees C to give the Mg-imide products [(NacNac(Mes))-Mg(NCPh2)](2) (4) and [(NacNac(Mes))-Mg(NC(C6H4)(2))](2) (5), respectively. The mechanism for the loss of N-2 was considered computationally. Compounds 2 and 3 reacted with O-2 to liberate the tetrazene (Ph2N2)(2) 6 and the hydrazine ((C6H4)(2)CN)(2) 7, whereas reactions with Me3SiOSO2CF3 or Me3SiCl with 2 and 3 provide the related silyl imines 8 and 9, respectively.