Abstract The iodide TsiSiPhHI (Tsi=(Me 3 Si) 3 C) has been shown to react with a range of silver (I) salts, AgY, to give the corresponding species TsiSiPhHY; the reactions with AgOCN give either the isocyanate alone or a mixture of this with the normal cyanate, depending on the conditions. Surprisingly, whereas reaction with AgBF 4 in Et 2 O gives only TsiSiPhHF, the same reaction in CH 2 Cl 2 gives a mixture of this with the rearranged (Me 3 Si) 2 C ( ...