Rearrangements of tetrahydrofuryl- and tetrahydropyranyl-hydrosilanes to oxasilaalkanes, of acetoxymethyl-hydrosilanes to acetoxysilanes, and halogenomethyl-hydrosilanes to halogenosilanes in the presence of palladium catalyst have been studied. The reaction has been shown to proceed more rapidly in tetrahydrofuran and hexane than in benzene or acetonitrile. The progressive replacement of the methyl