Silicon-containing Strained Molecules

Treatment of zirconacyclopentanes and -pentenes with TMSCN provides zirco-nocene-imine complexes which serve for carbon-carbon bond-forming reaction with a variety of unsaturated bonds [676]. 

Carbon-Carbon Bond Formation with Silaqrclopropanes 

---

There is no large strain in silaindan and silacyclopentene structures containing sp -carbon atom in benzyl or allyl position with respect to the silicon. Therefore, the driving force of the catalytic ROP of the above monomers is the combination of a small strain with the presence of chemically active endocyclic Si-Cfienzyi or Si-CAllyl bonds. The existence of two active moieties in silacyclopentene molecules (the unsubstituted double bond and the Si-CAHyi bond) provides two ways for polymerization via rupture of endocyclic Si-C bonds (cationic and anionic ROP) and via metathesis polymerization by cleavage of endocyclic C=C bonds (ROMP). 

Cyclotrisilanes and related three-membered ring compounds containing one, two, or three silicon atoms have attracted considerable attention (1). The ring strain of these molecules allows them not only to be used for various efficient ring-expansion and ring-opening reactions (2), but also for the generation of low-coordinated and unsaturated silicon compounds, especitilly silylenes, silenes, and disilenes (1,3). 

---