Cyclic oligosilanes, synthesis

A second useful precursor for the synthesis of sterically overcrowded oligosilyl anions is octakis(trimethylsilyl)tetrasilacyclobutane (8) [3], a cyclic oligosilane which can easily be converted into HTSB-K (9) by selective cleavage of the Si-SiMes bond with rBuOK in THF [4], After removal of the solvent, a highly moisture- and air-sensitive yellow-orange powder was obtained, which could be identified by NMR spectroscopy as the THF adduct of 9 (Scheme 2). 

Many cyclic and linear transition metal-silicon compounds have been obtained by the elimination of alkali halides with the corresponding transition metal salts145,146. The synthesis and reactivity of the Fe-oligosilane systems have been studied in detail by Pannell147-154 and this area has been recently reviewed155. 

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