Hexamethyl-1,3,5-trisilacyclohexane

Trimethylsilyl-2-dimethyl(phenyl)silyl-l,l,3,3,5,5-hexamethyl-1,3,5-trisilacyclohexane and 2,2-Bis(trimethylsilyl)-l, 1,3,3,5,5-hexamethyl-l,3,5-trisilacyclohexane... 

The synthesis of simple derivatives pertaining to this class of compounds is achieved in approximately 90% yield through metallation of a CH2 group in hexamethyl-1,3,5-trisilacyclohexane with n-BuLi ... 

C8H2 5N03Si8, 2,2,4,4,6,6-Hexamethyl-5-(hydroxydimethylsilyl)-1,3-dioxa-5-aza-2,4,6-trisilacyclohexane, 42B, 521 C8H2sN8Si8, Octamethylcyclotetrasilazane (gas-ed), 17, 680... 

Generation of ChIoro(lithiomethyl)dimethylsilane. Treatment of (bromomethyl)chlorodimethylsilane in THF/ether with 1 equiv of n-butyllithium in hexanes at — 120°C produces chloro (lithiomethyl)dimethylsilane. This lithiated derivative spontaneously eliminates LiCl to give an intermediate silaethylene species, which undergoes dimerization to afford 1,1,3,3-tetramethyl-1,3-disilacyclobutane (45%), together with a small amount of l,l,3,3,5,5-hexamethyl-l,3,5-trisilacyclohexane (15%) (eq9). ... 

In reactions with organometallic agents, the Si-methylated partly C-brominated 1,3,5-trisilacyclohexanes exhibit some similarities — and a number of differences — to their Si-chlorinated C-chlorinated analogues. For example, the 2,2,4,4-tetrabromo-hexamethyl-l,3,5-trisilacyclohexane yields with n-BuLi the dialkylated derivative. 

The reactions of 2,2,4,4-tetrabromo-hexamethyl-l,3,5-trisilacyclohexane 409 with t-BuLi or EtMgBr yield ring contraction and ring cleavage. This is evident from the compounds in the following scheme which were isolated after hydrogenation of the SiBr groups by means of LiAlH. ... 

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