Patent ID: 7541473

Claim:
A process for preparing cyclopentadienyl system anions of the formula (VII), where the variables have the following meanings: R 1A -R 4 A are each, independently of one another, hydrogen, C 1 -C 20 -alkyl, C 2 -C 20 -alkenyl, C 6 -C 20 -aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part, NR 6A 2 , N(SiR 6A 3 ) 2 , OSiR 6A 3 , or SiR 6A 3 where the organic radicals R 1A -R 4A may also be substituted by halogens and two vicinal radicals R 1A -R 4A may also be joined to form a five- or six-membered ring, and/or two vicinal radicals R 1A -R 4A are joined to form a heterocycle which contains at least one atom selected from the group consisting of N, P, O, and S, R 6A are each, independently of one another, hydrogen, C 1 -C 20 -alkyl, C 2 -C 20 -alkenyl, or alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and two geminal radicals R 6A may also be joined to form a five- or six-membered ring, A is an unsubstituted, substituted or fused, heteroaromatic ring system, R 4B are each, independently of one another, hydrogen, C 1 -C 20 -alkyl, C 2 -C 20 -alkenyl, C 6 -C 20 -aryl, alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part or SiR 3B 3 , where the organic radicals R 4 B may also be substituted by halogens and two radicals R 4B may also be joined to form a five- or six-membered ring and R 3B are each, independently of one another, hydrogen, C 1 -C 20 -alkyl, C 2 -C 20 -alkenyl, C 6 -C 20 -aryl or alkylaryl having from 1 to 10 carbon atoms in the alkyl part and 6-20 carbon atoms in the aryl part and two radicals R 3B may also be joined to form a five- or six-membered ring, which comprises the step a) or a′), where, in step a), an A − heteroaromatic ring system anion comprising a negative charge on a carbon atom adjacent to a heteroatom in the A − heteroaromatic ring system is reacted with a fulvene of the formula (VIIIa) or, in step a′), an organometallic compound R 4B M B X B b where M B is a metal of group 1 or 2 of the Periodic Table of the Elements, X B is halogen, C 1 -C 10 -alkyl, alkoxy having from 1 to 20 carbon atoms in the alkyl radical and/or from 6 to 20 carbon atoms in the aryl radical, or R 4B and b is 0 when M B is a metal of group 1 of the Periodic Table of the Elements and is 1 when M B is a metal of group 2 of the Periodic Table of the Elements, is reacted with a fulvene of the formula (VIIIb):