Tetraindeno-Fused Cyclooctatetraene and Oligomeric Biindenyls by Oxidative Coupling of 2,2′1-Biindenyl

Lithiated biindenyls 2 and 4, prepared by deprotonation of 2,2'-biindenyl (1) and 10,11-dihydrodiindeno[1,2-b:2',1'-d]thiophene (3) with n-butyllithium, are oxidatively coupled to give oligomeric biindenyls (17) as well as tetraindeno-fused eight-membered rings (16, 19, 24).