摘要:
In the C-silylated methylenephosphonium salt [(Bu2P)-Bu-t=CHSiMe3](+) AlCl4- (6) cation and anion are separated in the solid state and in solution. Adding an excess of AlCl3, however, does not allow the synthesis of the methylenephosphonium salt 6' with Al2Cl7- as counteranion but leads to the adduct (Bu2PCl)-Bu-t-CHSiMe3 . Al2Cl6 (7) which was characterized by an X-ray analysis. Electron-rich pi-conjugated hydrocarbons Like fulvene 9 or anthracene 10 react with 6 (or 7) under formation of [2+4]-cycloadducts 11a,b and 12, respectively, while electron-poor systems (benzene, naphthalene, C-60) are unreactive. (C) 1997 Elsevier Science S.A.