Iron‐Catalyzed Dehydrogenative Coupling of Tertiary Silanes

Abstract

A variety of tertiary silanes, even those with functional substituents, undergo an unprecedented iron-catalyzed dehydrogenative coupling (see scheme) in a convenient approach to disilanes, including unsymmetrical disilanes and polymers with Si-Si bonds in the backbone. Consideration of the catalytic reaction pathway revealed the intermediacy of a hydrido(disilyl)iron(IV) complex.

Polyferrocenyldisiloxane from the Platinum-Catalyzed Reactions of Tertiary Bis(dimethylsilyl)ferrocene in a Polar Aprotic Solvent

“…At elevated temperatures, elimination of H 2 (g) in the presence of the Pt catalyst likely results in the reduction of DMF to NMe 3 . 11 Similarly, in DMSO solutions, the reaction proceeds with the evolution of H 2 (g) and the subsequent reduction of DMSO to Me 2 S. This type of solvent reduction in the presence of organosilanes (R n SiH 4-n ) with a Pt catalyst at ambient temperature in DMSO has been previously reported by Lukevits and co-workers, who described the stoichiometric conversion of such organosilanes to disiloxanes. 17 Attempts at the preparation of disiloxanes from the ambient Ptcatalyzed reactions of silanes in DMF by these same workers were unsuccessful.…”

“…Our current efforts, 12 a reinterpretation of the original report, 13 and others 14 have now correctly identified the polyferrocenyldisiloxane 8 as the main product of those reactions, along with detectable quantities of NMe 3 and H 2 (g). 11 It is of interest to note that ambient Fe-catalyzed (1:25 [cat. ]/[monomer]) UV-irradiated polymerizations of 6 yields low molecular weight polymer 8 in high yield after 24 h, whereas the thermally Pt-catalyzed reactions of 6 (1:92, 1:209, 1:357 [cat.…”

Nanoporous Metals as Novel Catalysts for Chemical Transformations☆

“…[47][48][49] This revealed that the base might play a significant role in this reaction and hence different bases, such as pyridine, Et 3 N, Et 2 NH, and PhNHMe, were added in the reaction mixture using acetonitrile as a solvent. Interestingly, acetonitrile that was ineffective in the absence of the base gave desired product in 98% yield when one equivalent of pyridine was added in the reaction.…”

Synthesis of a Fragment of Crystalline Silicon: Poly(Cyclosilane)

“…The molecule is found at sites of inversion symmetry and only one half of the molecule is crystallographically independent. [31][32][33][34] Dehydrocoupling is a step-growth polymerization in which the first Si À Si bond formation converts two primary silanes into a less-reactive secondary silane. Cyclohexasilane 1 in the chair conformation has C 2h symmetry, predicting unique 1 H NMR signals for the diastereotopic axial and equatorial silane protons.…”