Trialkylsilyl-substituted pentalene ligands

The reaction between [C8H6][Li(DME)]2 and chlorotrimethylsilane affords the trimethylsilyl-substituted dihydropentalene C8H6(SiMe3-1,4)2, which may be deprotonated with nBuLi in dimethoxyethane to give [C8H4(SiMe3-1,4)2][Li(DME)]2; the latter reacts with chlorotrimethylsilane to give C8H4(SiMe3-1,1',4,4')4. Similarly, treatment of [C8H6][Li(DME)]2 with triisopropylsilyl triflate gives C8H6(SiiPr3-1,4)2; deprotonation of the latter with KNH2 in diethyl ether affords [C8H4(SiiPr3-1,4)2][K]2, which has been crystallographically characterized and exhibits a chain structure in the solid state.