Diastereoselective Synthesis of Seven-Membered-Ring <i>trans</i>-Alkenes from Dienes and Aldehydes by Silylene Transfer

Silver-catalyzed silylene transfer to alkenes forms vinylsilacyclopropanes regioselectively. These allylic silanes undergo additions to aldehydes to form seven-membered-ring trans-alkenes with high diastereoselectivity. The high reactivity of the trans-alkenes is evidenced by their formal [1,3]-sigmatropic rearrangement reactions and the rapid additions of oxygen–hydrogen bonds across the carbon–carbon double bonds.