On the reaction of tin dichloride and of metallic tin with hydrochloric acid in the presence of alkenes. The question of trichlorostannane(IV) or chlorostannate(II) intermediates.

Studies of the reaction of tin dichloride and of metallic tin with hydrochloric acid gas in diethyl ether are described. On the basis of spectroscopic and analytical data it is concluded that the product is not to be regarded as a tin-hydrogen bonded analog of chloroform, viz. trichlorostannane(IV), and the formation of an equilibrium mixture of hydrogen trichlorostannate(II) and dihydrogen tetrachlorostannate(II) is tentatively suggested. The complexes slowly decompose as a result of diethyl ether cleavage, yielding ethanol and ethyl chloride, together with traces of ethyltin trichloride.The mechanism of addition of the complexes to methyl acrylate is discussed in terms of a 1,4-addition involving initial protonation of oxygen. Reaction of the resulting β-carbomethoxyethyltin trichloride with tin or with zinc gives rise to mixtures of bis(β-carbomethoxyethyl)tin dichloride and tris(β-carbomethoxyethyl)tin chloride Similar reactions were observed for the first time with methyltin trichloride, the reaction with zinc being extremely fast at room temperature.