A general approach to the synthesis of polyquinenes via the Weiss reaction. 10. Transient formation of cis-tetracyclo[7.2.1.04,11.06,10]dodeca-3,5,7,9-tetraene and an approach toward 10,11-dimethyl-cis-tetracyclo[7.2.1.04,11.06,10]dodeca-3,5,7,9-tetraene