Silenes electrophilic addition

Silene adducts probably react through the free silaethene, although the reaction with bromine may be an exception. Addition of bromine to 9 gives the expected dibromide, but the adduct, 9 THF, gives a mixture of the dibromide and the product >Si[0(CH2)4Br]C(Br)<. The formation of the latter suggests electrophilic addition to the Si=C bond before the dissociation of THF211. 

The only computation of an addition path of this type dealt with the addition of HCl to silene and identified a transition state for electrophilic addition296. It seems likely to us that a more thorough search will identify a nucleophilic attack path with an even more favorable transition state. 

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