Facile Catalytic Hydrosilylation of Pyridines

Gutsulyak, Dmitry V.; Est, Art van der; Nikonov, Georgii I.

doi:10.1002/ange.201006135

Cited by 57 publications

(31 citation statements)

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“…This reaction involves two interdependent catalytic cycles. First, borane-mediated hydride abstraction in the bisallylic position 7,8 of I releases the silicon-stabilized Wheland complex or benzene-stabilized silicon cation III (I→II→III) that eventually collapses to liberate hydrosilane IV and one molecule of benzene (III→IV). The borane Lewis acid then activates the thus-formed hydrosilane IV 9 to perform C=X bond hydrosilylation [10][11][12] through ion pair VI (IV→V→VI) 13 .…”

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confidence: 99%

Formal SiH4 chemistry using stable and easy-to-handle surrogates

2015

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Monosilane (SiH4) is far less well behaved than its carbon analogue methane (CH4). It is a colourless gas that is industrially relevant as a source of elemental silicon, but its pyrophoric and explosive nature makes its handling and use challenging. Consequently, synthetic applications of SiH4 in academic laboratories are extremely rare and methodologies based on SiH4 are underdeveloped. Safe and controlled alternatives to the substituent redistribution approaches of hydrosilanes are desirable and cyclohexa-2,5-dien-1-ylsilanes where the cyclohexa-1,4-diene units serve as placeholders for the hydrogen atoms have been identified as potent surrogates of SiH4. We disclose here that the commercially available Lewis acid tris(pentafluorophenyl)borane, B(C6F5)3, is able to promote the release of the Si-H bond catalytically while subsequently enabling the hydrosilylation of C-C multiple bonds in the same pot. The net reactions are transition-metal-free transfer hydrosilylations with SiH4 as a building block for the preparation of various hydrosilanes.

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confidence: 99%

Formal SiH4 chemistry using stable and easy-to-handle surrogates

2015

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“…This Highlights describes the latest report from this research group on catalysis by the complex in the hydrosilylation of pyridine. [10] Pyridine and its derivatives having chloro and methyl substituents at 3-and 5-positions undergo hydrosilylation with HSiMe 2 Ph in the presence of catalytic amounts of 1 (2-5 mol % of the substrate) to yield the N-silyl-4-hydropyridine derivatives, as shown in Equation (1). The reaction is complete within several hours at room temperature.…”

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1,4‐Hydrosilylation of Pyridine by Ruthenium Catalyst: A New Reaction and Mechanism

Osakada

2011

Angew Chem Int Ed

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homogeneous catalysis · hydrosilylation · pyridine · rutheniumThe hydrosilylation of unsaturated molecules is recognized as the most common means of introducing a silicon-containing functionality to organic substrates. Complexes of various transition metals are employed as homogeneous catalysts for the hydrosilylation of C=C and C=O bonds.[1] Reports on the hydrosilylation of C=N bonds, however, were even much less common than those on the reaction of C=O bonds until recently. Over the past 15 years, complexes of various metals, including early-, late-, and post-transition metals (including Ti, [2] Re, [3] Ru, [4] Rh, [5] Ir, [6] Cu, [7] and Zn [8] ), have been reported to catalyze the addition of SiÀH groups of primary or secondary organosilanes or of polymethylhydrosiloxanes (PMHS) to imines. Since no hydrogenation of imines, giving the corresponding amines, takes place under mild conditions, the hydrosilylation of prochiral imines and the subsequent hydrogenolysis of the N À Si bond formed provide an alternative for the conversion of prochiral imines into optically active amines.Nikonov et al. of Brock University chose a cationic ruthenium complex, [Cp(iPr 3 P)Ru(NCMe) 2 ][B(C 6 F 5 ) 4 ] (1; Cp = cyclopentadienyl), as the catalyst for the hydrosilylation of ketones and nitriles in their recent studies.[9] This catalyst converts aliphatic and aromatic nitriles into the corresponding N-silylimines with high chemoselectivity or into N,Ndisilylamines formed by double hydrosilylation, depending on the reaction conditions. This Highlights describes the latest report from this research group on catalysis by the complex in the hydrosilylation of pyridine. [10] Pyridine and its derivatives having chloro and methyl substituents at 3-and 5-positions undergo hydrosilylation with HSiMe 2 Ph in the presence of catalytic amounts of 1 (2-5 mol % of the substrate) to yield the N-silyl-4-hydropyridine derivatives, as shown in Equation (1). The reaction is complete within several hours at room temperature.[Cp 2 TiMe 2 ] catalyzes the hydrosilylation of pyridine, which is the sole precedent using a homogeneous catalyst. [11] The reaction, however, requires higher amounts of the titanium catalyst (10 mol % of the substrate) and heating the reaction mixture at 80 8C. The 1,2-addition of the Si À H group in the hydrosilylation was confirmed by deuteriumlabeling experiments. The actual products are tetrahydropyridine derivatives which result from the concurrent hydrogenation of the pyridine ring. Thus, hydrosilylation using the half-sandwich ruthenium complex as the catalyst differs in chemoselectivity from the reaction catalyzed by the titanium complex and proceeds under milder conditions.The experimental results in this recent article may encourage creative applications by the readers who are interested in the reaction mechanism. Scheme 1 summarizes the reactions of N-silyl-4-hydropyridine (2) catalyzed by the complex 1. PhCN reacts with 2 in the presence of the catalyst 1 leading to the formation of N-silylphenylimine and the re...

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“…Die B(C 6 F 5 ) 3 -aktivierten Hydrosilane B kçnnten dann mit einem Alken G zur Reaktion gebracht werden, [7,8] und die Gesamtreaktion entspräche einer noch nicht bekannten ionischen Transferhydrosilylierung von Alkenen (D!H; Schema 1, unten). [9,10] Um die Gültigkeit unserer Hypothese zu beurteilen, stellten wir die Trimethylsilyl-und Dimethylsilyl-substituierten Cyclohexa-1,4-diene 1 und 2 sowie einige repräsentative triorganosilylierte Abkçmmlinge 3-5 her (Abbildung 1). Mit der optimierten Reaktionsvorschrift unterzogen wir verschiedene terminale und interne Alkene der Transferhydrosilylierung.…”

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3‐Silylierte Cyclohexa‐1,4‐diene als Vorstufen für gasförmige Hydrosilane: die B(C₆F₅)₃‐katalysierte Transferhydrosilylierung von Alkenen

Simonneau

Oestreich

2013

Angewandte Chemie

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Facile Catalytic Hydrosilylation of Pyridines

Cited by 57 publications

References 82 publications

Formal SiH4 chemistry using stable and easy-to-handle surrogates

Formal SiH4 chemistry using stable and easy-to-handle surrogates

1,4‐Hydrosilylation of Pyridine by Ruthenium Catalyst: A New Reaction and Mechanism

3‐Silylierte Cyclohexa‐1,4‐diene als Vorstufen für gasförmige Hydrosilane: die B(C₆F₅)₃‐katalysierte Transferhydrosilylierung von Alkenen

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Facile Catalytic Hydrosilylation of Pyridines

Cited by 57 publications

References 82 publications

Formal SiH4 chemistry using stable and easy-to-handle surrogates

Formal SiH4 chemistry using stable and easy-to-handle surrogates

1,4‐Hydrosilylation of Pyridine by Ruthenium Catalyst: A New Reaction and Mechanism

3‐Silylierte Cyclohexa‐1,4‐diene als Vorstufen für gasförmige Hydrosilane: die B(C6F5)3‐katalysierte Transferhydrosilylierung von Alkenen

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3‐Silylierte Cyclohexa‐1,4‐diene als Vorstufen für gasförmige Hydrosilane: die B(C₆F₅)₃‐katalysierte Transferhydrosilylierung von Alkenen