A Single Terminal [Ni^II−OH] Catalyst for Direct Julia‐Type Olefination and α‐Alkylation Involving Sulfones and Alcohols

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(35)

Published: April 22, 2024

Abstract A terminal [Ni II −OH] complex 1 , supported by triflamide‐functionalized NHC ligands, showed divergent reactivity for the reaction of sulfone with alcohol, contingent on base concentration, temperature, and time. Julia‐type olefination alcohols sulfones was achieved using one equiv. base, whereas lowering loading to 0.5 afforded α ‐alkylated sulfones. Besides excellent substrate scope selectivity, biologically active stilbene derivatives DMU‐212, pinosylvin, resveratrol, piceatannol were synthesized in high yield under conditions. An extensive array controlled experiments DFT calculations provide valuable insight pathway.

Language: Английский

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Silver‐Catalyzed Olefination of Aryl Aldehydes Using Propiolates

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(48)

Published: June 11, 2024

Olefination of aldehydes is one the fundamental reactions in organic synthesis. The commonly used Wittig olefination reaction however uses stoichiometric quantities reagents under basic conditions resulting amounts byproducts. Known catalytic alternate to requires silane reducing agents and high temperature. Herein, we report a base-free aryl using propiolates as surrogate for Witting reagent silver catalysis. Trimethyl orthoformate, presence catalyst adds alkynoate form nucleophilic allenolate which reacts with reactive oxocarbenium ion formed from aldehyde conditions. Subsequently, decarbonylation occurs olefin. Trans olefin exclusively simple cinnamaldehydes. Such conceptually novel has not been explored so far.

Language: Английский

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Nitrobenzene and Aniline‐Mediated Direct Olefination of Methyl Substituted N‐Heteroarenes With Benzylic Alcohols

ChemistrySelect, Journal Year: 2024, Volume and Issue: 9(44)

Published: Nov. 1, 2024

Abstract Metal‐free, strong‐base‐free, and solvent‐free synthesis of alkenyl heteroarenes through PhNO 2 /PhNH mediated direct olefination methyl substituted N ‐heteroarenes with benzylic alcohols was described. Detailed mechanistic studies indicated that in situ formed imine the active intermediate for olefination. protected from overoxidation, PhNH not only acted as coupling partner formation imine, but also provides an alkaline condition generation enamine salt. Gram scale reaction three pharmaceutically relevant conjugated olefins were successful using this methodology.

Language: Английский

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Pd/S cooperativity: from stoichiometric activation of Si−H bonds to catalytic hydrosilylation

ChemistryEurope, Journal Year: 2024, Volume and Issue: 3(1)

Published: Nov. 12, 2024

Abstract With the aim to explore metal‐ligand cooperation across Pd−S linkages, we designed a quinoline‐based PNS tridentate ligand and prepared Pd(II) complexes thereof. Optimal solubility stability of dicationic complex [(PNS)Pd(II)] 2 2+ IV were achieved with B(C 6 F 5 ) 4 – as counter‐anion. It adopts thiolate‐bridged dimeric structure (PdS) core, but readily activates hydrosilanes linkage. The resulting mononuclear hydride [(PNS SiR3 )Pd(II)H] + VI was characterized by multi‐nuclear NMR spectroscopy Si−H bond coordination/activation studied computationally. Complex found efficiently catalyze hydrosilylation alkynes, internal well terminal, good stereo regioselectivity.

Language: Английский

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Recent Advances in Homogeneous Catalysts for the Acceptorless Dehydrogenation of Alcohols to Ketones and Aldehydes

Journal of Organometallic Chemistry, Journal Year: 2024, Volume and Issue: 1024, P. 123445 - 123445

Published: Nov. 16, 2024

Language: Английский

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