Darstellung und reaktionen von 1,2-diaza-3-sila-5-Cyclopentenen

(Fluorosilyl)hydrazones are obtained from the reaction of lithiated hydrazones with fluorosilanes. On subsequent reaction with tert-butyllithium, cyclization takes place, to give 1,2-diaza-3-sila-5-cyclopentenes; this cyclization is favoured by the nitrogen-substituent of the hydrazone. The CH₂ group of the heterocyclic compounds is a nucleophilic centre, at which further substitutions are possible. The mass spec- trum and ¹H-, ¹⁹ F- and 2⁹Si-NMR spectra are reported.