Sila-Wittig rearrangements

Treatment of the (.V)-( A )-[(.svr-allylo y )dimcsitylsilyl]stannanc with -BuLi provides a (R)-(.E)-allylsilane with high enantioselectivity, in which 1,3-chirality transfer occurs during the [2,3]-sila-Wittig rearrangement (Equation (118)).290... 

Allyloxysilyl)lithiums undergo a [2,3]Wittig-type rearrangement smoothly to form allylsilanolate anions in an intramolecular fashion (Scheme 11). This is the first example of the sila-Wittig rearrangement (54g). 

The reactivity of the intramolecularly coordinated silenes 929, 934, and 935 has been investigated. The hydrolysis and methanolysis of 929 proceed via formation of Si-O bonds and yield the products 936 and 937 (Scheme 132). The reaction of 929 with benzaldehyde can be regarded as sila-Wittig reaction, and proceeds via the initial formation of the cycloaddition product 938, which rearranges into the cyclodisiloxane [R(Me3Si)SiO]2 939 (R = 8-dimethylamino-naphthyl-l-yl) and l,l-bis(trimethylsilyl)-2-phenylethene 940 (Scheme 132). Methyl iodide catalyzes the isomerization of 929, which proceeds via addition to the Si-C... 

The Still-Wittig rearrangement is hig functionality. A sila-version of the rear toxic tin compounds. 

The Still-Wittig rearrangement is highly (Zj-selective if assisted by a proximal oxy functionality. A sila-version of the rearrangement may have advantages in avoiding the toxic tin compounds. 

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