- Manganese-Catalyzed Dehydrogenative Silylation of Alkenes following Two Parallel Inner-Sphere Pathways
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We report on an additive-free Mn(I)-catalyzed dehydrogenative silylation of terminal alkenes. The most active precatalyst is the bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)]. The catalytic process is initiated by migratory insertion of a CO ligand into the Mn-alkyl bond to yield an acyl intermediate which undergoes rapid Si-H bond cleavage of the silane HSiR3 forming the active 16e- Mn(I) silyl catalyst [Mn(dippe)(CO)2(SiR3)] together with liberated butanal. A broad variety of aromatic and aliphatic alkenes was efficiently and selectively converted into E-vinylsilanes and allylsilanes, respectively, at room temperature. Mechanistic insights are provided based on experimental data and DFT calculations revealing that two parallel reaction pathways are operative: an acceptorless reaction pathway involving dihydrogen release and a pathway requiring an alkene as sacrificial hydrogen acceptor.
- Weber, Stefan,Glavic, Manuel,St?ger, Berthold,Pittenauer, Ernst,Podewitz, Maren,Veiros, Luis F.,Kirchner, Karl
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supporting information
p. 17825 - 17832
(2021/11/04)
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- Practical synthesis of allylic silanes from allylic esters and carbamates by stereoselective copper-catalyzed allylic substitution reactions
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The first copper-catalyzed allylic substitution reactions of allylic acetates and carbamates employing a bis(triorganosilyl)zinc reagent are reported. This novel procedure avoids the use of stoichiometric amounts of copper salts which are usually mandatory with this chemistry. Application of this methodology to standard model substrates substantiates a high diastereoselectivity for the double bond geometry (E:Z) as well as the relative configuration (syn:anti).
- Oestreich, Martin,Auer, Gertrud
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p. 637 - 640
(2007/10/03)
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- Conjugate Addition of the Phenyldimethylsilyl Group to αβ-Unsaturated Carbonyl Compounds Using a Silylzincate in Place of the Silylcuprate
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Lithium phenyldimethylsilyl(dialkyl)zincates add to a number of αβ-unsaturated carbonyl compounds to give, in most cases, higher yields of the conjugate addition product than we had achieved with the corresponding silylcuprate.
- Crump, Roger A. N. C.,Fleming, Ian,Urch, Christopher J.
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p. 701 - 706
(2007/10/02)
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- Reaction of triorgano(triorganogermyl)silanes with alkaly-metal allyl alcoholates
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Reaction of the lithium alcoholates of 1-vinylcyclohexanol (2a) (±)-linalool (2b), and 1-octen-3-ol (2c) with (dimethylphenylgermyl)trimethylsilane (3a) gave selective the corresponding allyldimethylphenylgermane derivatives (5a,c,e). Similar treatment with dimethylphenyl(trimethylgermyl)silane (3b) gave mixtures of the allyltrimethylgermanes (5b,d,f) and allyldimethylphenylsilanes (7b,d,f), whereas use of the potassium alcoholates afforded selectively 5b,d,f.
- Kabaki,Inoue,Sato
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p. 459 - 466
(2007/10/02)
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- Observations on Various Silyl-Cuprate Reagents
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The mixed silyl-cuprate reagent (6), made from 1 equiv. of methyl-lithium, 1 equiv. of phenyldimethylsilyl-lithium, and 1 equiv. of copper(I) cyanide, reacts with 3-methylcyclohexenone (7), with methyl cinnamate (9), with 1-vinylcyclohexyl acetate (11), a
- Fleming, Ian,Newton, Trevor W.
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p. 1805 - 1808
(2007/10/02)
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