The Chemistry of Silacyclopropenes

The synthesis and reactions of silacyclopropenes are summarized. Addition of silylenes to acetylenes and photochemical isomerization of alkynyldisilanes are known as two major routes for the synthesis of silacyclopropenes. Silacyclopropenes had been thought to be highly reactive and difficult to handle until the first crystal structure of a stable one was reported in 1980. Currently, however, it is commonly accepted that those molecules are stable under ambient conditions when sufficiently bulky substituents are introduced onto the strained three‐membered ring system to stabilize it kinetically. The reactivity of silacyclopropenes is interesting and depends on the nature of substituents. They, indeed, undergo a variety of reactions, such as photolysis, thermolysis, and transition‐metal‐catalyzed reactions, leading to the formation of reactive intermediates including silylenes and silapropadienes, and their transition‐metal complexes, through which numerous transformations into silicon‐containing cyclic and acyclic compounds are possible.