Synthesis and reactivity of a tethered diene cyclopentadiene, (C5Me4H)SiMe2(CH2CH&z.dbnd6;CHCH&z.dbnd6;CH2), and its alkali metal salts

(C5Me4H)SiMe2Cl reacts with (THF)KCH2CH&z.dbnd6;CHCH&z.dbnd6;CH2 to form (C5Me4H)SiMe2(CH2CH&z.dbnd6;CHCH&z.dbnd6;CH2) (1). Compound 1 reacts with KH and n-BuLi to make M(C5Me4)SiMe2(CH2CH&z.dbnd6;CHCH&z.dbnd6;CH2), M=K, 2; Li, 3, respectively. Carbon–silicon cleavage occurs when 1 reacts with K to form (C5Me4H)K, which crystallizes from dimethoxyethane as [(C5Me4H)K(DME)]x. This potassium salt has an extended structure which generates bent metallocene (C5Me4H)2K(DME) sub-structures which have 133.9° ring centroid&z.sbnd;K&z.sbnd;ring centroid angles. Compound 1 reacts with TiCl4 to make (C5Me4H)TiCl3 (5), which has a piano stool structure. [Copyright &y& Elsevier]