One-Pot Condensation of a Bicyclo[1.1.1]pentasilane through Elimination of Iodotrimethylsilane Assisted by a Lewis Base

Development of efficient bond formation reactions remains important in organic and main-group-element chemistry. Herein, we report the metal-free one-pot condensation reaction of 1-iodo-3-trimethylsilyl-substituted bicyclo[1.1.1]­pentasilane (BPS) in the presence of 4-(dimethylamino)­pyridine (DMAP) providing oligomers of BPS, persila­[n]­staffanes (n = 2, 3), which involves the successive Si–Si bond formation reaction accompanied by the concomitant formation of iodotrimethylsilane (TMSI) in the form of a DMAP complex. The computational study suggests that the formation of a pentasila[1.1.1]­propellane–DMAP complex resulting from the elimination of TMSI from the BPS is a key intermediate.