Generation of stannabenzenes and their monomer-dimer equilibration

Stannabenzene has not been isolated so far because of its high reactivity. In order to synthesize and isolate a stable stannabenzene, we have introduced two steric protection groups, the Tbt (2,4,6-tris[bis(trimethylsilyl)methyl]phenyl) or the Bbt (2,6-bis[bis(trimethylsilyl)methyl]-4-[tris(trimethylsilyl)methyl]phenyl) group on the tin atom and the t -butyl group on the 2-position, to the stannabenzene skeleton. Such a combination of steric protection groups was found to suppress the dimerization of stannabenzene to some extent, giving an equilibrated mixture of the corresponding stannabenzene and its dimer. A combination of bulky aryl and t -butyl groups was found to suppress the dimerization of stannabenzene, giving a monomer/dimer equilibration mixture.