摘要:
A protocol for the catalytic synthesis of indole-fused benzosiloles starting from 2-aryl-substituted indoles and dihydrosilanes is reported. Compared to known procedures, this method does not require prefunctionalized, starting materials and, hence, allows for a rapid access to those siloles. The net reaction is a 2-fold electrophilic C-H silylation catalyzed by cationic Ru-S complexes. Both reaction steps were separately investigated, and these results eventually led to the development of a two-step procedure. By preparing new Ru-S complexes with different weakly coordinating anions (WCAs), it is also shown that the latter can have a dramatic influence on the outcome of these reactions. Furthermore, the substrate scope of the new method is discussed.