Siloxy Alkynes in Annulation Reactions

Siloxy alkynes are a family of versatile species in organic synthesis. This account reviews the annulation reactions of siloxy alkynes for the synthesis of a variety of carbo‐ and heterocyclic products. With various dipolarophiles or dipolarophile‐like reaction partners, siloxy alkynes are capable of forming small (three‐ to six‐membered) rings. Recently, we have expanded the scope to the synthesis of medium‐ and large‐ring lactones, enabled by the design of new amphoteric molecules as well as a new ring‐expansion strategy. These annulation reactions provide not only practically useful syntheses of cyclic molecules, but also important understanding of the fundamental reactivity of siloxy alkynes.