Silylium Ion Promoted Reduction of Imines with Hydrosilanes

Müther, Kristine; Mohr, Jens; Oestreich, Martin

doi:10.1021/om4002796

Cited by 57 publications

(29 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[44] Oestreich has recently proposed that backside attack of a [R3Si-H-SiR3] + species by an imine could be a viable pathway for silylium-catalyzed imine hydrosilation, provided that the silicon substrate is not sterically hindered. [45] Thorough mechanistic studies are needed to assess whether Si-H-Si species are viable intermediates during catalysis.…”

Section: Silicon Catalystsmentioning

confidence: 99%

Electrophilic Activation of Silicon–Hydrogen Bonds in Catalytic Hydrosilations

2017

View full text Add to dashboard Cite

Hydrosilation reactions represent an important class of chemical transformations and there has been considerable recent interest in expanding the scope of these reactions by developing new catalysts. A major theme to emerge from these investigations is the development of catalysts with electrophilic character that transfer electrophilicity to silicon via Si-H activation. This type of mechanism has been proposed for catalysts ranging from Group 4 transition metals to Group 15 main group species. Additionally, other electrophilic silicon species, such as silylene complexes and η 3 -H2SiRR' complexes, have been identified as intermediates in hydrosilation reactions. In this Review, different types of catalysts are compared to highlight the range of hydrosilation mechanisms that feature electrophilic silicon centers, and the importance of these catalysts to the development of new hydrosilation reactions is discussed.

show abstract

Section: Silicon Catalystsmentioning

confidence: 99%

Electrophilic Activation of Silicon–Hydrogen Bonds in Catalytic Hydrosilations

2017

View full text Add to dashboard Cite

show abstract

“…Most commonly used and well-studied photo-initiatable catalysts are platinum-based ones such as a A novel method for obtaining α-silyl carbonyl products using B(C 6 F 5 ) 3 as catalyst was reported by Kim and Chang [69]. Unlike previously reported hydrosilylations of unsaturated polar bonds (such as carbonyls, imines, and nitriles [70][71][72]), the authors demonstrated the feasibility of the chemoselective α-silylation of conjugated esters and amides, in which the carbonyl group was left intact (Figure 29). According to preliminary mechanistic studies, the reaction proceeds in two steps, namely rapid 1,4-hydrosilylation of conjugated carbonyls and slow silyl group migration of a silyl ether intermediate.…”

Section: Light-initiated Hydrosilylation Reactionsmentioning

confidence: 99%

Fifty Years of Hydrosilylation in Polymer Science: A Review of Current Trends of Low-Cost Transition-Metal and Metal-Free Catalysts, Non-Thermally Triggered Hydrosilylation Reactions, and Industrial Applications

2017

View full text Add to dashboard Cite

Hydrosilylation reactions, the (commonly) anti-Markovnikov additions of silanes to unsaturated bonds present in compounds such as alkenes and alkynes, offer numerous unique and advantageous properties for the preparation of polymeric materials, such as high yields and stereoselectivity. These reactions require to be catalyzed, for which platinum compounds were used in the initial stages. Celebrating the 50th anniversary of hydrosilylations in polymer science and, concomitantly, five decades of continuously growing research, hydrosilylation reactions have advanced to a level that renders them predestined for transfer into commercial products on the large scale. Facing this potential transfer, this review addresses and discusses selected current trends of the scientific research in the area, namely low-cost transition metal catalysts (focusing on iron, cobalt, and nickel complexes), metal-free catalysts, non-thermally triggered hydrosilylation reactions (highlighting stimuli such as (UV-)light), and (potential) industrial applications (highlighting the catalysts used and products manufactured). This review focuses on the hydrosilylation reactions involving alkene reactants.

show abstract

“…Next, the intramolecular electrophilic addition of the silyl cation moiety of A to the C-C triple bond produces ethenyl carbocation B, which is stabilized by the β-silyl effect of the trimethylsilyl group. Finally, the hydride abstraction of B from another 1 affords benzosilole 2 and regenerates intermediate A [27][28][29], which acts as a chain carrier. from 1f being less stable than those derived from 1a-e, which are stabilized by double β-silyl effects.…”

Section: Methodsmentioning

confidence: 99%

Intramolecular Chain Hydrosilylation of Alkynylphenylsilanes Using a Silyl Cation as a Chain Carrier

et al. 2016

View full text Add to dashboard Cite

Diorganyl[2-(trimethylsilylethynyl)phenyl]silanes 1a-c and methyl-substituted phenylsilanes 1d and 1e were treated with a small amount of trityl tetrakis(pentafluorophenyl)borate (TPFPB) as an initiator in benzene to afford the corresponding benzosiloles (2a-e) in moderate to good yields. However, no reaction was observed for the reaction using [2-(1-hexynyl)phenyl]diisopropylsilane lf. The methyl substituent was tolerated under the reaction conditions and increased the yield of the corresponding benzosilole depending on the substitution position. From the result using 1f, the current reaction was found to require the trimethylsilyl group, which can stabilize intermediary alkenyl carbocations by the β-silyl effect. The current reaction can be considered an intramolecular chain hydrosilylation of alkynylarylsilanes involving silyl cations as chain carriers. Therefore, the silyl cations generated by hydride abstraction from hydrosilanes 1 with the trityl cation causes intramolecular electrophilic addition to the C-C triple bond to form ethenyl cations, which abstract a hydride from 1 to afford benzosiloles 2 with the regeneration of the silyl cations.

show abstract

Silylium Ion Promoted Reduction of Imines with Hydrosilanes

Cited by 57 publications

References 38 publications

Electrophilic Activation of Silicon–Hydrogen Bonds in Catalytic Hydrosilations

Electrophilic Activation of Silicon–Hydrogen Bonds in Catalytic Hydrosilations

Fifty Years of Hydrosilylation in Polymer Science: A Review of Current Trends of Low-Cost Transition-Metal and Metal-Free Catalysts, Non-Thermally Triggered Hydrosilylation Reactions, and Industrial Applications

Intramolecular Chain Hydrosilylation of Alkynylphenylsilanes Using a Silyl Cation as a Chain Carrier

Contact Info

Product

Resources

About