| Abstract: | Among the variety of isolable compounds with multiple bonds involving silicon, examples of compounds that contain silicon–boron double bonds (borasilenes) still remain relatively rare. Herein, we report the synthesis of the potassium salt of a chloride adduct of borasilene 1 ( 2 ]−), which was obtained as an orange crystalline solid. Single‐crystal X‐ray diffraction analysis and reactivity studies on 2 ]− confirmed the double‐bond character of the Si=B bond as well as the reduced Lewis acidity, which is due to the coordination of Cl− to the boron center. A thermal reaction of 2 ]− afforded a bicyclic product by formal intramolecular C−H insertion across the Si=B bond of 1 , which was corroborated by a theoretical study. |
