Cross-coupling Reaction based on the Transformation of Trialkylsilyl Groups

The cross-coupling reaction employing organosilicon compounds is one of the most important carbon-carbon bond-forming reactions. This reaction usually proceeds in the presence of a palladium catalyst and a base such as fluoride anion. Due to many advantages in the silicon-based cross-coupling reaction, this transformation has attracted much attention for the past decades. Especially, organo(trialkyl)silanes are characterized by robustness, low toxicity, good solubility, and easy handling. There properties are ideal for synthesis of bioactive agents and organofunctional materials such as π-electron conjugated molecules. However, these organo(trialkyl)silanes are difficult to be employed in the cross-coupling reactions, most probably because of their exceeding robustness. Thus, a practical method to use them for cross-coupling nucleophiles has been a long-standing challenging research target. We have developed the copper-catalyzed cross-coupling using heteroaryl(trialkyl)silanes or aryl(trialkyl)silanes having an electron-withdrawing substituent on the reacting aryl ring with aryl halides or alkyl halides. This method allows us to construct a variety of biaryls and teraryls. Moreover, the concept of the trialkylsilyl-based cross-coupling is applicable to the formation of a carbon-nitrogen bond. N-Trimethylsilyl-amines underwent the cross-coupling with aryl halides catalyzed by a palladium or a nickel catalyst with a base. The present article describes the concept of reaction design and the details of the experimental outcomes.