Platinum-Catalyzed Reduction of DMF by 1,1,3,3-Tetramethyldisiloxane, HMeSi2OSiMe2H: New Intermediates HSiMe2OSiMe2OCH2NMe2 and HSiMe2(OSiMe2)3OCH2NMe2 and Their Further Chemical Reactivity

Abstract

The use of Karstedt's catalyst to study the reduction of Me₂NCHO (DMF) by the popular "dual SiH"-containing tetramethyldisiloxane, HMe₂SiOSiMe₂H (1), has revealed that the first step in the process involves an initial single hydrosilylation to form HSiMe₂OSiMe₂OCH₂NMe₂ (3). This intermediate is readily isolated and purified via distillation. In the continued presence of the catalyst, 3 transforms to the transient tetrasiloxane HMe₂SiOSiMe₂OSiMe₂OSiMe₂OCH₂NMe₂ (4), along with the formation of Me₃N. The tetrasiloxane 4 itself transforms to Me₃N and (Me₂SiO) _n (n = 4-6). Despite the demonstrated reactivity of 3, it can also be used to perform the expected metal-catalyzed hydrosilylation chemistry of the SiH group as well as reactions of the SiOCH₂NMe₂ functionality involving siloxane chain extension and is thus an important new reagent for siloxane chemistry.