First, we examined the synthesis of a stannole skeleton by the debrominative cyclization of 1. Treatment of 1 with 2 equiv of tert-butyllithium in THF at −90 °C gave a yellow solution. After usual workup, the mixture was chromatographed to gave bi(1,1-stannole) (58%) as yellow crystals together with stannole 3 (7%) (Scheme 2). Compound 2 was proved to have a symmetrical structure by its 13 C NMR, and its structure was finally established by X-ray structural analysis (Fig. ...
