Hypervalent Iodine Reagent Useful for the Chemical Synthesis of Diatomic Carbon

Trimethylsilylethynyl(phenyl)iodonium tetrafluoroborate (1) has been reported as a precursor to ethynyl(phenyl)iodonium tetrafluoroborate (2), which is useful for the α-ethynylation of β-dicarbonyl compounds.¹⁾

Miyamoto and Uchiyama et al. reported that treating 1 with tetrabutylammonium fluoride or cesium fluoride generates diatomic carbon (C₂) at room temperature, which can be trapped by 9,10-dihydroanthracene or galvinoxyl free radical.²⁾ They also demonstrated that C₂ can be used as a molecular element for the bottom-up synthesis of nanocarbons. Another group has reported the synthesis of N-(acyloxy)ynamides using this method.³⁾ A computational study suggested potential alternative pathways to form trapped compounds that do not involve free C_2.⁴⁾ Although both computational and experimental studies have been conducted, no definitive conclusions have been reached.⁵⁾ Thus, 1 has been attracting attention not only for ethynylation reactions but also for studies in C₂ chemical synthesis and its applications.

Related Products

P1239

Trimethylsilylethynyl(phenyl)iodonium Tetrafluoroborate

E0467

Ethynyl(phenyl)iodonium Tetrafluoroborate

P3256

Phenyl[(trimethylsilyl)ethynyl]iodonium Triflate

P1008

Potassium tert-Butoxide

D0549

9,10-Dihydroanthracene

G0020

Galvinoxyl Free Radical

C2204

Cesium Fluoride

References

• 1) Synthesis of ethynyl(phenyl)iodonium tetrafluoroborate. A new reagent for ethynylation of 1,3-dicarbonyl compounds
  • M. Ochiai, T. Ito, Y. Takaoka, Y. Masaki, M. Kunishima, S. Tani, Y. Nagao, J. Chem. Soc. Chem. Commun. 1990, 118.
• 2) Room-temperature chemical synthesis of C₂
  • K. Miyamoto, S. Narita, Y. Masumoto, T. Hashishin, T. Osawa, M. Kimura, M. Ochiai, M. Uchiyama, Nat. Commun. 2020, 11, 2134.
• 3) Synthesis of N-(acyloxy)-N-alkynylamides via generation of “C₂” from hypervalent alkynyliodane and a weak base
  • K. Kagami, X. Liang, N. Ishibashi, S. Ohrui, M. Tayu, N. Saito, Chem. Commun. 2023, 59, 8274.
• 4) Routes involving no free C₂ in a DFT-computed mechanistic model for the reported room-temperature chemical synthesis of C₂
  • H. S. Rzepa, Phys. Chem. Chem. Phys. 2021, 23, 12630.
• 5) A combined DFT-predictive and experimental exploration of the sensitivity towards nucleofuge variation in zwitterionic intermediates relating to mechanistic models for unimolecular chemical generation and trapping of free C₂ and alternative bimolecular pathways involving no free C₂
  • H. S. Rzepa, M. Arita, K. Miyamoto, M. Uchiyama, Phys. Chem. Chem. Phys. 2022, 24, 25816.

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