Transfer Hydrocyanation of α‐ and α,β‐Substituted Styrenes Catalyzed by Boron Lewis Acids

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(11), P. 3579 - 3583

Published: Jan. 9, 2019

Abstract A straightforward gram‐scale preparation of cyclohexa‐1,4‐diene‐based hydrogen cyanide (HCN) surrogates is reported. These are bench‐stable but formally release HCN and rearomatize when treated with Lewis acids. For BCl 3 , the formation isocyanide adduct [(CN)BCl ] − corresponding Wheland complex was verified by mass spectrometry. In presence 1,1‐di‐ trisubstituted alkenes, transfer from surrogate to C−C double bond occurs, affording highly substituted nitriles Markovnikov selectivity. The success this hydrocyanation depends on acid employed; catalytic amounts (C 6 F 5 ) 2 shown be effective while B(C BF ⋅OEt not.

Language: Английский

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Catalyst-free transfer hydrogenation of activated alkenes exploiting isopropanol as the sole and traceless reductant

Green Chemistry, Journal Year: 2023, Volume and Issue: 25(2), P. 746 - 754

Published: Jan. 1, 2023

Described herein is an unconventional catalyst-free transfer hydrogenation reaction of activated alkenes using isopropanol as eco-friendly reductant and solvent.

Language: Английский

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B(C₆F₅)₃-catalyzed transfer hydrogenations of imines with Hantzsch esters

Organic & Biomolecular Chemistry, Journal Year: 2018, Volume and Issue: 16(9), P. 1448 - 1451

Published: Jan. 1, 2018

Transfer hydrogenations of imines with Hantzsch esters were realized using 0.1 mol% B(C₆F₅)₃, and up to 38% ee was obtained for asymmetric reactions.

Language: Английский

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Ionic Transfer Reactions with Cyclohexadiene-Based Surrogates

Synlett, Journal Year: 2019, Volume and Issue: 30(20), P. 2216 - 2232

Published: Nov. 6, 2019

A current research program in our laboratory is devoted to the development of cyclohexa-1,4-diene-based surrogates difficult-to-handle compounds and their application metal-free ionic transfer reactions. These investigations grew from interest silylium ion chemistry consequently concentrated initially on gaseous explosive hydrosilanes such as Me3SiH even monosilane (SiH4). Since then, we have expanded concept design other species including H2, mineral acids (HI HBr), hydrocarbons (isobutane isobutene). This Account summarizes discoveries this area date, describing challenges faced along way how combatted them. 1 Introduction 2 Transfer Hydrofunctionalization: Variation Electrofuge 3 Nucleofuge 4 Hydrohalogenation Using a Modified Surrogate 5 Synthesis 6 Conclusion

Language: Английский

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Regiodivergent DH or HD Addition to Alkenes: Deuterohydrogenation versus Hydrodeuterogenation

Organic Letters, Journal Year: 2020, Volume and Issue: 22(4), P. 1628 - 1632

Published: Feb. 11, 2020

The regioselective and regiodivergent addition of H-D to a variety 1,1-diarylalkenes was realized utilizing selectively deuterated dihydroaromatic compounds, which were generated by cobalt catalysis. reaction initiated catalytic amounts BF3·Et2O abstracting hydride or deuteride ions from the respective reducing agents led highly incorporation deuterium hydrogen at desired positions starting material.

Language: Английский

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Indium‐Catalysed Transfer Hydrogenation for the Reductive Cyclisation of 2‐Alkynyl Enones towards Trisubstituted Furans

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(44), P. 23661 - 23666

Published: Sept. 3, 2021

Indium tribromide catalysed the transfer hydrogenation from dihydroaromatic compounds, such as commercially available γ-terpinene, to enones, which resulted in cyclisation trisubstituted furan derivatives. The reaction was initiated by a Michael addition of hydride nucleophile enone subunit followed Lewis-acid-assisted and formation furan-indium intermediate Wheland derived starting material. product formed protonation complex replaced indium substituent. In addition, site-specific deuterium labelling HD surrogates site specific products gave useful insights into mechanism H-D scrambling.

Language: Английский

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Nickel-Catalyzed Cross-Coupling of Umpolung Carbonyls and Alkyl Halides

The Journal of Organic Chemistry, Journal Year: 2019, Volume and Issue: 84(10), P. 6312 - 6322

Published: April 19, 2019

An effective nickel-catalyzed cross-coupling of Umpolung carbonyls and alkyl halides was developed. Complementary to classical alkylation techniques, this reaction utilizes as the environmentally benign nucleophiles, providing an efficient selective catalytic alternative traditional use highly reactive organometallic reagents.

Language: Английский

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Metal-Free Transfer Hydrobromination of C–C Triple Bonds

Organic Letters, Journal Year: 2019, Volume and Issue: 21(12), P. 4531 - 4534

Published: May 31, 2019

A transfer hydrobromination of C-C triple bonds inititated by Brønsted acids is reported. Hydrogen bromide released stepwise from a bench-stable cyclohexa-1,4-diene-based surrogate, generating biphenyl and ethylene as waste. range vinyl bromides was prepared terminal internal, mainly acceptor-substituted alkynes with good functional-group tolerance.

Language: Английский

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Nitrenium Salts in Lewis Acid Catalysis

Angewandte Chemie, Journal Year: 2019, Volume and Issue: 132(7), P. 2737 - 2741

Published: Dec. 6, 2019

Abstract Molecular compounds featuring nitrogen atoms are typically regarded as Lewis bases and extensively employed donor ligands in coordination chemistry or nucleophiles organic chemistry. By contrast, electrophilic nitrogen‐containing much rarer. Nitrenium cations a new family of nitrogen‐based acids, the reactivity which remains largely unexplored. In this work, nitrenium ions explored catalysts five transformations. These reactions first examples acid catalysis employing site substrate activation. Moreover, these readily accessed from commercially available reagents exhibit remarkable stability toward moisture, allowing for benchtop transformations without need to pretreat solvents.

Language: Английский

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Contra-thermodynamic Olefin Isomerization by Chain-Walking Hydrofunctionalization and Formal Retro-hydrofunctionalization

Organic Letters, Journal Year: 2019, Volume and Issue: 21(17), P. 7129 - 7133

Published: Aug. 19, 2019

We report a contra-thermodynamic isomerization of internal olefins to terminal driven by redox reactions and formation Si–F bonds. This process involves chain-walking hydrosilylation subsequent formal retro-hydrosilylation. The rests upon the high activities platinum catalysts for metal alkyl intermediates new, metal-free conversion alkylsilanes alkenes. By this approach, 1,2-disubstituted trisubstituted are converted olefins.

Language: Английский

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