Platinum-Catalyzed Reduction of DMF by 1,1,3,3-Tetramethyldisiloxane, HMeSi(2)OSiMe(2)H: New Intermediates HSiMe(2)OSiMe(2)OCH(2)NMe(2) and HSiMe(2)(OSiMe(2))(3)OCH(2)NMe(2) and Their Further Chemical Reactivity

[Image: see text] The use of Karstedt’s catalyst to study the reduction of Me(2)NCHO (DMF) by the popular “dual SiH”-containing tetramethyldisiloxane, HMe(2)SiOSiMe(2)H (1), has revealed that the first step in the process involves an initial single hydrosilylation to form HSiMe(2)OSiMe(2)OCH(2)NMe(2) (3). This intermediate is readily isolated and purified via distillation. In the continued presence of the catalyst, 3 transforms to the transient tetrasiloxane HMe(2)SiOSiMe(2)OSiMe(2)OSiMe(2)OCH(2)NMe(2) (4), along with the formation of Me(3)N. The tetrasiloxane 4 itself transforms to Me(3)N and (Me(2)SiO)(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 SiOCH(2)NMe(2) functionality involving siloxane chain extension and is thus an important new reagent for siloxane chemistry.