Geometrically Compelled Silicon(II)/Silicon(IV) Donor–Acceptor Interaction Enables the Enamination of Nitriles

Discovering new bonding scenarios and subsequently exploring the reactivity contribute substantially to advance the main group element chemistry. Herein, we report on the isolation and characterization of an intriguing class of the hydrido‐benzosiloles 2–4. These compounds exhibit a side arm of the amidinatosilylenyl group, featuring unidirectional silicon(II)/silicon(IV) donor‐acceptor interaction on account of the geometric constraint. Furthermore, the reactions involving 2–4 with nitriles yield the tricyclic compounds that edge‐fused of the Si‐heteroimidazolidine‐CN2Si2, silole‐C4Si, and phenyl‐C6‐rings (5–13). These compounds are manifesting a unique reaction that the silicon(II)/silicon(IV) interaction enables the enamination of the α‐H‐bearing nitriles. The reaction mechanism involved in H‐shift under oxidative addition at silylene followed by hydrosilylation of a ketenimine intermediate was revealed by density function theory (DFT) calculations. Hydrido‐benzosiloles bearing a side arm of the silylenyl group are prepared, all featuring the unique silicon(II)→silicon(IV) donor‐acceptor interaction that facilitates the enamination of α‐H‐bearing nitriles to afford the edge‐fused Si‐heterotricycles.