Aluminum chloride catalyzed skeletal rearrangement of permethylated cyclic polysilanes

Rearrangement/Fragmentation Reactions of Oligosilanes with Aluminum Chloride

“…In the course of our studies we found that in general Al(Fe)Cl 3 -catalyzed reactions of branched oligosilanes which are isomeric with materials already studied by the Kumada group 7 − 10 led to the same results. However, a few reactions showed an additional twist.…”

“…( 9 ) Explicitly it was noted that no other isomers were detected by spectroscopic analysis. ( 9 ) In contrast to that, the rearrangement of 2,2,5-tris(trimethylsilyl)undecamethylhexasilane ( 1 ) with Al(Fe)Cl 3 led to the almost quantitative formation of 1,1,3-tris(trimethylsilyl)heptamethylcyclopentasilane ( 2 ) 10 , 12 and tetramethylsilane (Scheme 1 ).…”

Cationic Si−H−Si Bridges in Polysilanes: Their Detection and Targeted Formation in Stable Ion Studies

“…This concept has been demonstrated for the rearrangements of cyclohexasilanes 12 to yield silylcyclopentasilanes 13 (Scheme ) . This reaction is a prototype for ring‐contraction reactions mediated by strong Lewis acids, which are important tools for the skeletal modification of polysilanes.…”

“…Although the number of applications of silyl cations in synthesis and catalysis has increased in recent years, experimental investigations of polysilanyl‐substituted silyl cations, such as cation 6 , are rather scarce. This is even more surprising as these cations are believed to be important intermediates in skeletal rearrangement reactions of oligosilanes and a deeper understanding of their nature and reactivity could pave the way to a controlled and directed modification of oligo‐ and polysilanes . Exploratory investigations by Lambert and Zhang revealed the thermolability of even such small representatives as tris(trimethylsilyl)silylium, (Me 3 Si) 3 Si + .…”

Wagner–Meerwein-Type Rearrangements of Germapolysilanes - A Stable Ion Study

“… 1 Regarding the potential for such materials being useful for technical applications, there is intrinsic interest in novel approaches that open the possibility to develop new synthetic tools for the preparation of open chain, cyclic, and polyhedral compounds with silicon containing backbones. Pioneering work by the group of Kumada and Ishikawa, 4 further developed by the groups of West, 5 Märkl, 6a and Pannell, 6b revealed that the Lewis acid catalyzed Wagner–Meerwein-type rearrangement of oligosilanes is a powerful method to create structures of higher complexity. The high yield synthesis of an all-silicon analogue of adamantane from a structural isomer, reported previously by two of us, is certainly one of the more spectacular examples for the potential of this synthetic methodology.…”