Highly Active Titanocene Catalysts for Epoxide Hydrosilylation: Synthesis, Theory, Kinetics, EPR Spectroscopy

Henriques, Dina Schwarz G.; Zimmer, Katharina; Klare, Sven; Meyer, Andreas; Rojo‐Wiechel, Elena; Bauer, Mirko; Sure, Rebecca; Grimme, Stefan; Schiemann, Olav; Flowers, Robert A.; Gansäuer, Andreas

doi:10.1002/anie.201601242

Cited by 62 publications

(25 citation statements)

References 54 publications

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“…A milder method for the in situ generation of [Cp 2 TiH] from bench stable Cp 2 TiCl 2 employs allylMgBr for the preparation of [Cp 2 Tiallyl] [14] (allyl activation) [15] . This species is then transformed into [Cp 2 TiH] by σ‐bond metathesis with PhSiH 3 .…”

Section: Resultsmentioning

confidence: 99%

Titanocene(III)‐Catalyzed Precision Deuteration of Epoxides

et al. 2021

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We describe a titanocene(III)‐catalyzed deuterosilylation of epoxides that provides β‐deuterated anti‐Markovnikov alcohols with excellent D‐incorporation, in high yield, and often excellent diastereoselectivity after desilylation. The key to the success of the reaction is a novel activation method of Cp2TiCl2 and (tBuC5H4)2TiCl2 with BnMgBr and PhSiD3 to provide [(RC5H4)2Ti(III)D] without isotope scrambling. It was developed after discovering an off‐cycle scrambling with the previously described method. Our precision deuteration can be applied to the synthesis of drug precursors and highlights the power of combining radical chemistry with organometallic catalysis.

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Section: Resultsmentioning

confidence: 99%

Titanocene(III)‐Catalyzed Precision Deuteration of Epoxides

et al. 2021

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“…Furthermore,w hy,i fC p 2 Ti(H)Cl is ar obust species,h ad nobody succeeded in its isolation?W ec learly needed some thermodynamic insight into aprotic catalysis.A ndreas Gansäuer and his student Sven Klare had successfully applied DFT calculations to other Ti III reactions. [15] We requested them to examine the thermal stability of Cp 2 Ti(H)Cl and also the thermodynamics of its reaction with Me 3 SiCl.…”

Section: Mystery 1: the Case Of The Vanishing Intermediatementioning

confidence: 99%

Four Mechanistic Mysteries: The Benefits of Writing a Critical Review

Nugent

RajanBabu

2020

Angewandte Chemie

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While writing ac omprehensive review on the reactions of epoxides with titanium(III) reagents,w ee ncountered as eries of mechanistic puzzles.U sing clues from the literature,many of whichwere not available at the time that the mysteries emerged, it was possible to demystify an umber of these conundrums.Wediscuss four examples,whichwebelieve will significantly change the way in which titanium(III) chemistry is practiced. Our experience underscores the importance of comprehensive and critical reviews in chemistry and the truism that the authors are prime beneficiaries of the review process. Scheme 1. Some available reaction pathwaysf or b-titanoxyr adical 2.

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“…Based on experimental and computational data, ac atalytic cycle for the titanium(III)-mediated hydrosilylation of epoxides was proposed (Scheme 11). [24] The initial step would involve the generation of ac atalytically active species, 6,u pon the reaction of [TiCp 2 R 2 ]w ith the hydrosilane. Species 6 would then reversibly form silane adduct 6a.T he ring opening of the epoxide would take place with 6 to form aT i IV ÀHspecies containing tertiary carbon-centeredr adical 6b.S ubsequent radical re-Scheme10.…”

Section: Hydrosilylative Reduction Of Epoxidesmentioning

confidence: 99%

“…Based on experimental and computational data, a catalytic cycle for the titanium(III)‐mediated hydrosilylation of epoxides was proposed (Scheme ) . The initial step would involve the generation of a catalytically active species, 6 , upon the reaction of [TiCp 2 R 2 ] with the hydrosilane.…”

Section: Hydrosilylative Reduction Of Epoxidesmentioning

confidence: 99%

Catalytic Reduction of Cyclic Ethers with Hydrosilanes

Park

2019

Chemistry An Asian Journal

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Catalytic reductive transformations of ethers as a synthetic building block are an important class of chemical reactions because a range of essential chemical feedstocks and fuels in contemporary life can be prepared through the key step of ethereal C−O bond cleavage of cellulosic biomass. Although conventional stoichiometric and catalytic methods for sp2‐ and sp3‐C−O bond cleavage of linear ethers and alcohols with hydrosilanes are well established, silylative ring opening of cyclic ethers has been less highlighted in this context. This review outlines catalytic systems for the silylative reduction of a range of cyclic ethers, including epoxides and sugars, leading to the corresponding alcohols and/or hydrocarbons. The chemical reactivity and selectivity of these ring‐opening catalytic processes are discussed with respect to the type of substrates; the representative catalytic working modes are also described.

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Highly Active Titanocene Catalysts for Epoxide Hydrosilylation: Synthesis, Theory, Kinetics, EPR Spectroscopy

Cited by 62 publications

References 54 publications

Titanocene(III)‐Catalyzed Precision Deuteration of Epoxides

Titanocene(III)‐Catalyzed Precision Deuteration of Epoxides

Four Mechanistic Mysteries: The Benefits of Writing a Critical Review

Catalytic Reduction of Cyclic Ethers with Hydrosilanes

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