Description:
AbstractTo establish some steric protection at the P center of a tricyclic 1,4‐dihydro‐1,4‐phosphasiline, the potassium salt of a tricyclic 1,4‐dihydro‐1,4‐phosphasilin‐1‐ide was treated with triphenylmethyl chloride. Subsequently, the two Si‐bound diethylamino groups, were converted to give the SiCl2 derivative using HCl. The Si‐functionality could be used in substitution reactions thus giving Si‐dimethyl and Si‐dimethoxy derivatives. Reduction of the SiCl2 derivative at low temperature gave transient tricyclic silylene which could not be detected by NMR spectroscopy but successfully trapped by 1,3‐butadiene to give a P‐containing spiro‐silolene derivative. DFT studies provide insight into reduction and the silylene formation.