Abstract Isopropenylpentamethyldisilane, 1, 2-diisopropenyltetramethyldisilane and 1, 3- diisopropenylhexamethyltrisilane were prepared by the reaction of isopropenylmagnesium bromide with the corresponding chlorosilanes. It was found that all these compounds readily undergo intramolecular rearrangement with concentrated sulfuric acid in the cold to give, after treatment with ammonium hydrogen fluoride, fluorsilanes with the SiC (CH 3) 2 Si ...