σ‐Holes in Iodonium Ylides: Halogen‐Bond Activation of Carboxylic Acids, Phenols and Thiophenols May Enable Their X−H Insertion Reactions

Chemistry - A European Journal, Journal Year: 2022, Volume and Issue: 28(71)

Published: Sept. 29, 2022

The first systematic evaluation of the electrostatic potential energy maps iodonium ylides was conducted. We determined that they possess two σ-holes differing electron deficiencies, with more electropositive σ-hole located opposite dative I-C bond to β-dicarbonyl motif, and lesser iodoarene C-I bond. also conducted carboxylic acids, phenols thiophenols in O/S-alkylation reaction ylides. While acids were found be generally viable, only possessing electron-withdrawing substituents effective. This high-yielding highly chemoselective is believed involve halogen-bond activation heteroatoms, nicely complements existing diazo-based methods for alkylation acidic functional groups.

Language: Английский

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Steric and Electronic Effect on C₂‐H Arylation of Sulfonamides

ChemistrySelect, Journal Year: 2019, Volume and Issue: 4(23), P. 7010 - 7014

Published: June 19, 2019

Abstract The ambident nature of the electrophile generated in a reaction system controls outcome reaction. Electrophilic nitrenium ion which is convertible to carbenium via resonance was situ by reactions iodine(III)‐reagent PhI(OAc) 2 and arylsulfonamides. nucleophile added for regiospecific ortho C−H arylation or C ‐H arylation. electron rich arenes react with (electrophiles) undergo Electron donating effect (+I +R effect) substituents on sulfonamide stabilizes favor oxidative coupling nucleophiles. Overall, feasibility sulfonamides has been demonstrated steric electronic factor that facilitates sulfonamides.

Language: Английский

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[Co(TPP)]–Catalyzed Carbene Transfer from Acceptor–Acceptor Iodonium Ylides via N-enolate Carbene Radicals

Published: June 15, 2021

Abstract: Square-planar cobalt(II)-systems have emerged as powerful carbene transfer catalysts for the synthesis of a variety (hetero)cyclic compounds via redox non-innocent Co(III)-carbene radical intermediates. Spectroscopic detection and characterization these reactive intermediates has thus far been limited to few scattered experiments, in part due fact that most studies focused on mono-substituted precursors. In this work, we demonstrate unique formation disubstituted cobalt(III)-carbene radicals reactions between cobalt(II)-porphyrin com-plex with acceptor-acceptor iodaneylidenes (iodonium ylides) We report detailed spectroscopic resulting species, their application styrene cyclopropanation. particular, iodonium ylides generate novel bis-carbenoid species leading reversible substrate-promoted ligand modification commercially available [Co(TPP)]-catalyst. Two interconnected catalytic cycles are involved overall reaction mono-terminal an unprecedented N-enolate-carbene intermediate respective key mono- bis-carbene cycles. Notably, N-enolate is not catalyst deactivation pathway, both moieties can be transferred units styrene. The provide picture new [Co(TPP)]-catalyzed from ylides. findings supported by unequivocal & products (EPR, UV-Vis, HR-MS, NMR, in-situ ATR-FT-IR, SC-XRD), Hammett analysis, mechanistic control DFT pathway profiling NEVPT2-CASSCF electronic structure calculations.

Language: Английский

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[Co(TPP)]–Catalyzed Carbene Transfer from Acceptor–Acceptor Iodonium Ylides via N-enolate Carbene Radicals

Published: June 15, 2021

<b>Abstract: </b>Square-planar cobalt(II)-systems have emerged as powerful carbene transfer catalysts for the synthesis of a variety (hetero)cyclic compounds via redox non-innocent Co(III)-carbene radical intermediates. Spectroscopic detection and characterization these reactive intermediates has thus far been limited to few scattered experiments, in part due fact that most studies focused on mono-substituted precursors. In this work, we demonstrate unique formation disubstituted cobalt(III)-carbene radicals reactions between cobalt(II)-porphyrin com-plex with acceptor-acceptor iodaneylidenes (iodonium ylides) We report detailed spectroscopic resulting species, their application styrene cyclopropanation. particular, iodonium ylides generate novel bis-carbenoid species leading reversible substrate-promoted ligand modification commercially available [Co(TPP)]-catalyst. Two interconnected catalytic cycles are involved overall reaction mono-terminal an unprecedented N-enolate-carbene intermediate respective key mono- bis-carbene cycles. Notably, N-enolate is not catalyst deactivation pathway, both moieties can be transferred units styrene. The provide picture new [Co(TPP)]-catalyzed from ylides. findings supported by unequivocal & products (EPR, UV-Vis, HR-MS, NMR, in-situ ATR-FT-IR, SC-XRD), Hammett analysis, mechanistic control DFT pathway profiling NEVPT2-CASSCF electronic structure calculations.<br>

Language: Английский

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