Olefin Isomerization and Hydrosilylation Catalysis by Lewis Acidic Organofluorophosphonium Salts

Pérez, Manuel; Hounjet, Lindsay J.; Caputo, Christopher B.; Dobrovetsky, Roman; Stephan, Douglas W.

doi:10.1021/ja410379x

Cited by 179 publications

(106 citation statements)

References 37 publications

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“…This observation is similar to that reported for the hydrosilylation of methoxy-α-methylstyrenes (23). The carboxylic acid p-C 8 H 17 (C 6 H 4 )CO 2 H and Et 3 SiH gave the corresponding ester in less than 1 h (entry 21).…”

Section: Resultssupporting

confidence: 88%

“…The species [(C 6 F 5 ) 3 PF][B(C 6 F 5 ) 4 ] 1 proved to be an effective catalyst for the hydrodefluorination of fluoroalkanes in the presence of silane (22). We subsequently showed that 1 could effectively catalyze the hydrosilylation of olefins and alkynes (23). In this report, we first exploit the Lewis acidity of 1 to catalyze the dehydrocoupling of silane with a variety of species including amines, thiols, phenols, and carboxylic acids, liberating H 2 .…”

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confidence: 99%

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Metal-free transfer hydrogenation of olefins via dehydrocoupling catalysis

Pérez

Caputo

Dobrovetsky

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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145

111

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A major advance in main-group chemistry in recent years has been the emergence of the reactivity of main-group species that mimics that of transition metal complexes. In this report, the Lewis acidic phosphonium salt [(C 6 F 5 ) 3 PF][B(C 6 F 5 ) 4 ] 1 is shown to catalyze the dehydrocoupling of silanes with amines, thiols, phenols, and carboxylic acids to form the Si-E bond (E = N, S, O) with the liberation of H 2 (21 examples). This catalysis, when performed in the presence of a series of olefins, yields the concurrent formation of the products of dehydrocoupling and transfer hydrogenation of the olefin (30 examples). This reactivity provides a strategy for metalfree catalysis of olefin hydrogenations. The mechanisms for both catalytic reactions are proposed and supported by experiment and density functional theory calculations. fluorophosphonium A wide range of commodity chemicals, petrochemicals, pharmaceuticals, materials, and foods depend on industrial-scale hydrogenation reactions. Catalysts for this process are based on both heterogeneous transition metals materials and homogeneous transition metal complexes. Indeed, it was the discovery of Sabatier (1) in the early 20th century that revealed the utility of amorphous Ni and other metals in hydrogenation processes. Following the dawn of organometallic chemistry in the 1960s, homogeneous catalysts were developed principally based on precious metals (2-4). Although subsequent modifications and optimizations have led to numerous highly selective and efficient catalyst technologies, concerns over cost, natural abundance, and toxicity have prompted efforts to uncover catalysts based on "earth-abundant" elements. The principal targets in these efforts have been the first-row transition metals. Indeed, the groups of Chirik (5, 6), Morris (7), Beller (8), and others (9) have developed remarkably active and selective catalysts based on Fe.Strategies to develop reduction methods using organic or main-group-based reagents have also been explored. For example, use of Hantzsch esters (10), Birch reduction of arenes (11), or the use of B or Al hydrides are effective, albeit stoichiometric reductions. More recently, the advent of "frustrated Lewis pairs" (FLPs) have led to the discovery that combinations of sterically encumbered donors and acceptors act as catalysts for the reductions of imines, enamines, silylenol ethers, olefins, and alkynes (12).To uncover hydrogenation strategies using earth-abundant elements, we have focused our efforts on Lewis acidic phosphorus species. Although Gudat (13), Burford and coworker (14), Yoshifuji (15), and Bertrand and coworker (16), among others, have reported phosphenium cations that demonstrate Lewis acidity, Radosevich and coworkers (17) have exploited the reaction of the unique planar P(III) species with ammoniaborane to give a P(V)H 2 derivative that effects the subsequent reduction of diazobenzene. Although the acidity of P(V) has been exploited previously in ylide reagents (18), Diels-Alder reactions catalysis (19), and add...

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Section: Resultssupporting

confidence: 88%

mentioning

confidence: 99%

Metal-free transfer hydrogenation of olefins via dehydrocoupling catalysis

Pérez

Caputo

Dobrovetsky

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

145

111

View full text Add to dashboard Cite

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“…The fact that tertiary carbocations are more stable than secondary ones (the latter formed in-situ from nonsubstituted dienes) is reflected in the difference of attainable polymerization degrees. Using organofluorophosphonium salts as catalyst in relatively low catalyst loading of 1.5 mol %, Stephan and coworkers reported high yields (above 89%) for the hydrosilylation of various olefins and alkynes [56]. The reactions were performed at r.t. Based on calculation studies, they proposed a mechanism of the hydrosilylation and the phosphonium activation of hydrosilane.…”

Section: Non-metal Catalysts For 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

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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.

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“…Related trans-hydrosilylations have been achieved with organofluorophosphonium salts as Lewis acid. 44 These methods, however, have not yet been used in the context of natural product synthesis.…”

Section: Introductionmentioning

confidence: 99%

Progress in the trans-Reduction and trans-Hydrometalation of Internal Alkynes. Applications to Natural Product Synthesis

Frihed

Fürstner

2016

Bulletin of the Chemical Society of Japan

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The classical repertoire of synthetic organic chemistry is short of methods that allow triple bonds to be transformed into (E)-alkenes with high selectivity in the presence of other reducible sites. Recent advances, most notably in ruthenium-catalyzed trans-hydrogenation, trans-hydrosilylation, trans-hydrogermylation, trans-hydrostannation, and even trans-hydroboration hold the promise of filling this gap. This review illustrates the state-of-the-art in the field by summarizing applications of these emerging methodologies to natural product synthesis. A comparison of ruthenium-catalyzed and radical-induced trans-hydrostannations provides further insights into the application profile of these transformations

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Olefin Isomerization and Hydrosilylation Catalysis by Lewis Acidic Organofluorophosphonium Salts

Cited by 179 publications

References 37 publications

Metal-free transfer hydrogenation of olefins via dehydrocoupling catalysis

Metal-free transfer hydrogenation of olefins via dehydrocoupling catalysis

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

Progress in the trans-Reduction and trans-Hydrometalation of Internal Alkynes. Applications to Natural Product Synthesis

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