Dimethylallyl trimethylsilane

Preparative Methods treatment of trichlorosilane with 3-methylbut-2-en-l-ylmagnesium chloride followed by methylmagnesium bromide (2 equiv) provides (aja-dimethyl-allyl)dimethylsilane (bp 108 °C) in 76% yield with 99% isomeric purity. The hydrosilane is converted to the ethoxysi-lane quantitatively by the reaction with ethanol catalyzed by hydrogen hexachloroplatinate(IV), and then fluorinated in situ with tetrafluoroboric acid to give the fluorosilane in 87% yield. The latter is methylated with a small excess of methyllithium to give (Q, Q -dimethylallyl)trimethylsilane in 96% yield. Alternatively, (a,Q -dimethylallyl)trimethylsilane can be prepared from 3-methylbut-l-yn-3-ol in six steps.  

Handling, Storage, and Precautions can be stored in a glass bottle. 

Photochemical Prenylation. Photolysis of (a,a-dimethyl-allyl)trimethylsilane in the presence of l-methyl-2-phenyl-l-pyrrolinium perchlorate leads to the formation of a (3,3-dimethyl-prop-2-en-l-yl)pyrrolidine as the sole regioisomer (eq 5).  

Isomerization. (a, a -Dimethylallyl)trimethylsilane can undergo isomerization to (y,)/-dimethylallyl)trimethylsilane with fluoride ion catalysis.  

Prenylation of Acetals. (a,a-Dimethylallyl)trimethylsilane reacts with acetals in the presence of a Lewis acid to give the corresponding homoallyl alcohols with corr5)lete regioselectivity (eqs 1 and 2). The reaction with carbonyl compounds often leads to the formation of tetrahydrofuran derivatives (eq 3), presumably through the formation of chloride.  

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