Palladium-Catalyzed Synthesis of Silylated 3,3′-Bi(3,8-dihydrocyclopenta[<i>a</i>]indenyls) from Silylacetylenes

The reaction of <i>o-</i>iodo(trimethylsilylethynyl)benzenes with trimethylsilylacetylene in the presence of a Pd catalyst afforded the dimer of 8,8,10-tris(trimethylsilyl)-3,8-dihydrocyclopenta[<i>a</i>]indene as the sole identified product. Neither the regioisomer nor monomers were detected, which revealed that complete regiocontrol of silyl migration and dimerization occurred. Desilylation of the silylated dimers afforded dihydropentalene dimers through the simultaneous transposition of double bonds.