Synthesen und Kristallstrukturen der lithierten Silylphosphane (CMe3)2SiFP(Mes)Li(THF)3,(CMe3)2SiFLi(TMEDA)PMes und des cyclischen Silylphosphanes [(CMe3)2SiPMes)]2

Di-tert-butyldifluorsilne reacts with lithiated 2,4,6-trimethylphenylphosphane to give (CMe3)2SiFPHC6H2Me3 (1). A lithium derivative is formed in the reaction of 1 with nC4H9Li. The crystal structures of the lithium derivatives (CMe3)2SiFP(C6H2Me3)Li(THF)3 (2) and (CMe3)2SiFLi(TMEDA)PC6H2Me3(3) were determined. The phosphorus atom is planar in 2 and pyramidal in 3. A (SiPLiF)-four-membered ring is formed in 3. LiF-elimination leads to the formation of the (SiP)-four-membered ring (4). The ring system of 4 is completely asymmetrical, indicating that the sterical limits of the dimerisation of the intermediate silaphosphene have been reached. Both 2 and 3 react with CMe3SiF3 to give the substituted compound (CMe3)2SiFP(SiF2CMe3)C6H2 Me3 (5).