Synthese und Deprotonierung eines Phosphinomethylimidazoliumsalzes. Zur Delokalisierung der π‐Elektronen in Aminovinylphosphanen [1]

Tetrafluorobo‐Synthesis and Deprotonation of a Phosphinomethylimidazolium Salt. On the π‐Electron Delocalization im Aminovinyl Phosphanes 1] The ylidic olefin 1, 3, 4, 5‐tetramethyl‐2‐methyleneimidazoline ( 1 , Im=CH₂) reacts with chlorodiphenylphosphane to give the phosphane salt (Im‐CH₂)PPh₂]Cl ( 6 ) from which the vinylphosphane Im=CHPPh₂ ( 8 ) is obtained by deprotonation. 8 reacts with HBF₄ etherate to give the tetrafluoroborate salt (Im‐CH₂)‐PPh₂] BF₄ ( 7 ). The crystal structures of 7 and 8 are determined and discussed. In 8 , π‐electron delocalisation is indicated both by structural data and temperature dependent n.m.r. spectroscopy