Synthesis of azido(trimethylsilyl)acetylene (6) was performed by treating the iodonium salt 5 with highly soluble hexadecyltributylphosphonium azide (QN₃) at -40 °C. Although this product is very unstable, it can nevertheless be trapped by the click reaction with cyclooctyne to give the corresponding 1,2,3-triazole, and also directly characterized by ¹H- and (13)C-NMR data as well as IR-spectra, which were measured in solution at low temperature and in the gas phase. The thermal or photochemical decay of azide 6 leads to cyano(trimethylsilyl)carbene. This is demonstrated not only by quantum chemical calculations, but also by the trapping reactions with the help of isobutene.
Keywords: carbenes; ethynyl azides; gas phase IR data; photolysis; reactive intermediates.