Sila-Wittig reaction

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... 

Alkenes from a-silyl carbanion and carbonyl compounds. Also known as sila-Wittig reaction. 

The reactivity of early transition metal silylenoid complexes is still emerging. An example of the chemistry that these complexes can participate in is the sila-Wittig reaction [equation (7.4)].53 In this transformation, a metathesis occurred between the chromium silylenoid 24 and the dimethyl carbonate to afford a new Schrock carbene, 25, and the trimerized product 26. This methodology allowed access a new carbene complex that eluded previous synthetic efforts. 

It appeared that if heated at 160°C in a sila-Wittig-type reaction, 26 actually decomposes into the transient silanone Is2Si=0, which immediately dimerizes to 27 and the phosphaalkenes 28 and 28 (Scheme 6).14... 

Compound 23 decomposes on thermolysis at 160°C in a sila-Wittig-type reaction to furnish the transient silanone ls2Si=0, which immediately dimerizes to the l,3-disila-2,4-dioxetane 24, and the phosphaalkenes 25 and 25A (Scheme 6). l,3-Disila-2,4-dioxetanes are well known from the work of West et al. [28]. Because of the drastic reaction conditions, the expected phosphaalkene 25 partially isomerizes under phenyl and silyl group migration to 25A. However, such an isomerization process was previously unknown for phosphaalkenes,... 

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