CHEMICAL AND PHOTOCHEMICAL APPROACHES TO AMINO(ARYL)SILYLENES

Generation by two different methods of silylenes stabilized by o-amino(aryl) groups is reported. The halodemetallation of difluoro- or dichloro-silanes with Li metal or lithium-naphthalene gave the same product, a stabilized sila-ylide (hypercoordinated silylene). Intramolecular Lewis base stabilization is not sufficient to isolate a monomeric species. The silylenes, however, have been trapped with 2,3-dimethylbutadiene. An unexpected intramolecular rearrangement to silaacenaphthene has been observed in the case of a six-membered ring amino(aryl) coordinated silylene. Photolysis of o-1-[(N,N-dimethylamino)methyl]-2-[tris(trimethylsilyl)silyl]benzene produced, among other products, Me(3)SiSiMe(3) and the sila-ylide, which has been trapped with Et(3)SiH and dimethylbutadiene. Our mechanistic interpretation is supported by spectral observation of the photochemically generated reaction intermediates in a 3-methylpentane glass at low temperature.