Striking reactivity of a stable, zwitterionic silylene towards substituted diazomethanes, azides, and isocyanides.

The reactivity of the zwitterionic N-heterocyclic silylene (NHS) LSi: 1 (L = Ar-N-C(Me)=CH-C(=CH(2))-N-Ar, Ar = 2,6-iPr(2)C(6)H(3)), towards diphenyldiazomethane (Ph(2)CN(2)), trimethylsilyl azide (Me(3)SiN(3)), and cyclohexyl isocyanide (C(6)H(11)-NC) is reported. The addition of Ph(2)CN(2) to 1 leads to the diiminylsilane LSi(N=CPh(2))(2) 2 (80% yield), whereas the treatment of 1 with Me(3)SiN(3) gives the spirobicyclic silatetrazoline LSi(NNSiMe(3))(2) 3 (67% yield), and addition of C(6)H(11)-NC gives the silyl cyanide LSi(R)CN (R = cyclohexyl) 4 (32% yield) along with the unexpected azasilacyclobutane 5 (41% yield). The novel compounds were fully characterized by (1)H, (13)C, and (29)Si NMR spectroscopy, ESIMS, elemental analysis, and single-crystal X-ray diffraction.