Silenes, Peterson olefination

A relatively new synthetic approach to silenes was established independently in the laboratories of Oehme101-110, Apeloig39,111 and Ishikawa112,113. The key-step is a base-initiated 1,2-elimination of silanolate from at-hydroxydi si lanes 157 and formation of silenes 158 analogous to the original Peterson olefination reaction (equation 39). 

The [4 + 2] reaction with dienes has been frequently used to establish the intermediacy of a silene in the sila-Peterson olefination reaction39,107-112-1 r fulSj further examples for cycloadditions can be found in Section I.A.5. 

An acid-induced amino-sila-Peterson olefination of gemina] (dimethylamino)-bis(hypersilyl)methanes 263 with concentrated H2SO4 gives a transient 1,1,2-trisilylsilene 264 (Scheme 2.158) [441], The silene 264 is trapped in the presence of excess H2SO4, and further hydrolytic work-up affords the silanol 265. 

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