Silabenzenes reactivity

Despite the Tbt stabilization, the silabenzene and germabenzene are highly reactive towards water or alcohols (the RO residue adds to the heteroatom, and a hydrogen adds to a 2- or 4-carbon atom, destroying the aromaticity) benzophenone, styrene, and phenylacetylene afford bicyclo[2.2.2]octane-derivatives. In all these products, the heteroatom (Y = Si or Ge) has. sp3-hybridization. 

Although the resonance energy of silabenzene is calculated to be about three-fourths of that of benzene, silabenzenes are extremely reactive and, thus, have been examined only in frozen matrices and in the gas phase. By far the simplest route to silabenzenes is pyrolysis of the 1,4-dihydro derivatives. 

An interesting collection of reactive intermediates are involved in the decomposition of the diazo compound (35) or the diaziridine (36). The resulting carbene (37) in part rearranges to the silene (38) which is trapped as the silole (39), and in part rearranges to the silabenzene (40) which gives rise to the adducts (41) and (42) <83TL4245, 850M584>. 

Safety glasses and protective gloves must be used at all times. All manipulations must be carried out in standard Schlenk technique and inert glove box. Silabenzenes are very reactive, so it is advisable to perform the reaction under strict inert condition ... 

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