Polycylopentadienyls: synthesis of arylsilylcyclopentadienyl compounds and their η5-complexes with tungsten

Article abstract of DOI:10.1016/0022-328X(92)83456-R

A general route to arylsilylcyclopentadienyl compounds starting from 1,4-C6H4Br2, 2,6-C5NH3Br2 and 1,3,5-C6H3Br3 is described.The aryl bromides were treated with Mg/ClSiMe2H to give the aryldimethylsilanes 1,4-C6H4(SiMe2H)2, 2,6-C5NH3(SiMe2H)2, and 1,3,5-C6H3(SiMe2H)3 which after reaction with Cl2 or Br2 yielded the aryldimethylsilyl halides 1,4-C6H4(SiMe2Br)2, 2,6-C5NH3(SiMe2Br)2, 1,3,5-C6H3(SiMe2X)3 (X=Br or Cl) in excellent yields.The halide can be replaced by various cyclopentadienides to give aryldimethylsilylcyclopentadienes of the general type 1,4-C6H4(SiMe2Cp)2 and 1,3,5-C6H3(SiMe2Cp)3 (Cp=C5H5 (8,11), C5H3(t-C4H9)2 (9, 12), C5HMe4 (10, 13)).Compounds C6H5(SiMe2(C5H5)), 1,4-C6H4(SiMe2(C5H5))2 (8) and 1,3,5-C6H3(SiMe2(C5H5))3 (11) were in turn treated with NaH, (MeCN)3W(CO)3, and MeI to give the η⁵-bound complexes C6H5(SiMe2(C5H4)W(CO)3Me) (14), 1,4-C6H4(SiMe2(C5H4)W(CO)3Me)2 (15), 1,3,5-C6H3(SiMe2(C5H4)W(CO)3Me)3 (16), which contain up to three half-sandwich units within one molecule.