Condensations iodotrimethylsilane

At the end of his review [7] dealing with the acetalization of carbonyl compounds, Sakurai reported a previously unpublished observation. In the presence of catalytic amounts of iodotrimethylsilane and one equivalent of tetramethoxysilane 38, allyl-trimethylsilane 1 underwent smooth condensation with benzaldehyde 39, leading to adduct 41 in good yield. The silyl-modified Sakurai reaction was born (Scheme 13.15). 

Several preparative methods have been described for iodotrimethylsilane. Of these the reaction of hexamethyldisilane with iodine looks cleanest. A mixture of hexamethyldisi-lane (0.3 g, 2 mmol) and iodine (0.5 g, 2 mmol) is heated at ca 65 °C in a 20-mL flask fitted with a reflux condenser an exothermic reaction occurs and a homogeneous solution is formed. The mixture is then heated under reflux for 1.5 h. At this stage, hexamethyldisilane is converted quantitatively to iodotrimethylsilane (confirmed by NMR). 

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