Oligosilyl anions

The reactivity of the newly synthesized anions was studied. As expected, they can easily be protonated and alkylated, in close analogy to other silyl anions we have investigated earlier [3, 4]. Furthermore, oligosilyl anions were successfully used for the formation of interesting silicon-heteroatom bonds [9]. In a similar manner, vinylsilyl potassium compound 4b can be transmetalated into the Mg analog [10], and the respective anion can then be used as a nucleophile in the reaction... 

Interestingly, 2a is the sole reaction product obtained from 2 upon cleavage of one trimethylsilyl group. Metalation was found to occur selectively to give the higher silylated oligosilyl anion. This... 

Keywords oligosilyl anions, oligosilyl dianions. Group 4 silyl compounds... 

In the course of our studies of oligosilyl anions we have investigated alternative conditions for the generation of oligosilyl potassium compounds [4]. For example, we have employed tetramethylethylenediamine (tmen) / toluene solvent mixtures to obtain the tris(trimethylsilyl)silyl potassium (1) and l,l,4,4-tetrakis(trimethylsilyl)-2,2,3,3-tetramethyltetrasilanyl 1,2-dipotassium (2) tmen adducts (Eqs. 1,2). 

Eq. 1. Cleavage of one trimethylsilyl group to yield oligosilyl anion 1. 

In conclusion, we have been able to demonstrate the high potential of the easily accessible oligosilyl anions as precursors for the synthesis of silyl transition metal compounds. 

Experimental Determination of the Inversion Barriers of Oligosilyl Anions... 

Keywords oligosilanes, oligosilyl anions, chlorosilanes, fluorosilanes... 

Synthesis, Structure and Reactivity of Novel Oligosilyl Anions 219... 

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). 

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