(Me3N)Mo(CO)5-Catalyzed Reduction of DMF by Disiloxane and Disilane Moieties: Fate of the Silicon-Containing Fragments

Selective reduction of formamides to O-silylated hemiaminals or methylamines with HSiMe2Ph catalyzed by iridium complexes

The reaction of (4-methyl-pyridin-2-iloxy)ditertbutylsilane (NSitBu-H, 1) with [IrCl(coe)2]2 affords the iridium(iii) complex [Ir(H)(Cl)(κ2-NSitBu)(coe)] (2), which has been fully characterized including X-ray diffraction studies. The reaction of 2 with AgCF3SO3 leads to the formation of species [Ir(H)(CF3SO3)(κ2-NSitBu)(coe)] (3). The iridium complexes 2 and 3 are effective catalysts for the reduction of formamides with HSiMe2Ph. The selectivity of the reduction process depends on the catalyst. Thus, by using complex 2, with a chloride ancillary ligand, it has been possible to selectively obtain the corresponding O-silylated hemiaminal by reaction of formamides with one equivalent of HSiMe2Ph, while complex 3, with a triflate ligand instead of chloride, catalyzed the selective reduction of formamides to the corresponding methylamine.

Siloxymethylamines as Aminomethylation Reagents for Amines Leading to Labile Diaminomethanes That can be Trapped as Their [Mo(CO)4 ] Complexes

Compound Et3 SiOCH2 NMe2 transfers Me2 NCH2 to R2 NH (R2 =Et2 , PhMe, [Cr(η(6) -C6 H5 )(CO)3 ]Me, PhH) to form previously unknown diaminomethanes, Me2 NCH2 NR2 and, in the case of R2 =PhH, the triamine Me2 NCH2 N(Ph)CH2 NMe2 . The diaminomethanes exhibit an unreported disproportionation to a mixture of (R2 N)2 CH2 , (Me2 N)2 CH2 , and Me2 NCH2 NR2 , which can be trapped as their [Mo(CO)4 (diamine)] complexes. Whereas PhMeNCH2 NMe2 is a labile material, the metal-substituted ([(η(6) -C6 H5 )Cr(CO)3 ]MeNCH2 NMe2 is a stable material. The triamine Me2 NCH2 N(Ph)CH2 NMe2 is unstable with respect to transformation to 1,3,5-triphenyltriazine, but is readily trapped as the bidentate-triamineMo(CO)4 . All metal complexes were characterized by single-crystal X-ray diffraction.

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.

Tandem-reduction of DMF with silanes via necklace-type transition over Pt(0) nanoparticles: deciphering the dual Si–H effect as an extension of steric effects

The mechanism of the reduction of dimethylformamide to N(CH₃)₃ by the action of silanes and a heterogeneous Pt-catalyst is presented.