Lewis acid-catalyzed synthesis of silafluorene derivatives from biphenyls and dihydrosilanes via a double sila-Friedel-Crafts reaction.

The synthesis of silafluorene derivatives from aminobiphenyl compounds and dihydrosilanes via a double sila-Friedel-Crafts reaction using a borane catalyst has been achieved. This method is applicable to the synthesis of a variety of silafluorene derivatives, such as multisubstituted silafluorenes, spirosilabifluorenes, and silicon-bridged terphenyl compounds, which are not readily obtained using conventional synthetic methods. In addition, we have demonstrated the transformation of the amino groups in these silafluorene derivatives into other substituents.