Tunable Regiodivergent Reactivity of N-Allenamides with Silacyclobutanes via Palladium Catalysis in the Synthesis of Silacyclic β-Aminosilanes

The key structure of β-aminosilanes has attracted significant interest because of their latent biological activities in the field of medicinal chemistry. However, the structural variety of β-aminosilanes has been significantly constrained by the absence of a comprehensive synthetic approach. Thus, the development of regiodivergent catalytic systems for the construction of structurally diverse β-aminosilanes via an intermolecular cycloaddition strategy would represent a significant addition to the limited toolkit available for their synthesis. We herein present an attractive approach for the synthesis of β-aminosilanes through the regioselective cycloaddition of N-allenamides with the expansion of silacyclobutanes catalyzed by Pd/PR3. Just by selecting a suitable protecting group of N-allenamides, the regioselectivity of the cycloaddition is completely switched to efficiently provide two regioisomers of silacyclic β-aminosilanes. Two regioselectivities were proceeded during the migratory insertion and reductive elimination process, the origin of which could be well rationalized using density functional theory calculations.