Stabilizing properties of silicon in reactions of vinyl, allyl, allenyl and propargyl silanes, that proceeds via β-silyl carbenium ion, is commonly known as β-silicon effect. Mechanistic insights show two possible pathways of stabilization – vertical (e.g. hyperconjugation) or nonvertical (e.g. formation of silonium ion).1 Formation of closed silonium ion with combination of other stabilizing effects explains why many reactions involving β-silyl carbenium ion tend to undergo 1,2-silyl shift. Previously we have reported the use of propargylsilanes in the synthesis of silyl dienes and indenes by the catalytic amounts of strong Brønsted acids (TfOH, Tf2NH, Tf3CH) that involves 1,2-silyl shift.2 Herein we report the use of liquid sulfur dioxide for this transformation as highly polar and Lewis acidic reaction media which offers possibility to use weaker acids (e.g. BzOH, TsOH). Moreover, in a tandem cheletropic addition process silyl sulfolenes are obtained from the in situ formed dienes