Bildung und Umwandlung des instabilen 2-tert-Butyl-1,1-bis(trimethylsilyl)-silens

After deprotonation under elimination of trimethylsilanolate 1-hydroxy-2,2-dimethyl-1-tris(trimethylsilyl)silyl-propane 3, that can he made by interaction of tris(trimethylsilyl)silyl-magnesiumbromide with pivalinaldehyde, reacts according to a Peterson type mechanism to give the unstable 2-tert-butyl 1,1-bis(trimethylsilyl)-silene 4, that in absence of trapping agents dimerizes to 1,1,2,2-tetrakis(trimethylsilyl)-3,4-di-tert butyl-1,2 disilacyclobutane 5. Addition of tert-butyllithium or phenyllithium across the SiC bond of the transient 4 results in formation of neopentyl-tert-butyl-bis(trimethylsilyl)-silane 6 and licopentyl-phenyl-bis(trimethylsilyl)-silane 7, respectively; deprotonation of 3 in presence of 2,3-dimethylbutadiene leads to 3,4-dimethyl-6-tert-butyl-1,1-bis(trimethylsily)-1-silacyclohex-3-ene 8.