Apeloig-Ishikawa-Oehme-type silenes

Three different routes to the key compounds for the sila-Peterson elimination, the a-alkoxydisilanes 157, are described in the literature, namely A, reaction of silyllithium reagents with ketones or aldehydes B, addition of carbon nucleophiles to acylsilanes C, deprotonation of the polysilylcarbinols. In addition, method D, which already starts with the reaction of 2-siloxysilenes with organometallic reagents, leads to the same products. The silenes of the Apeloig-Ishikawa-Oehme type synthesized so far are summarized in Table 4. 

In contrast, l,l-silylsilenes ° ° ° and 2-siloxysilenes 3,86,90,180 j silenes of the Apeloig-Ishikawa-Oehme and Brook type as well as some 1-silaallenes , dimerize in a head-to-head mode yielding 1,2-disilacyclobutanes (equation 98). 

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