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

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.