Magic Acid Free Generation of Antiaromatic Dications at Room Temperature

Abstract

A new method for the generation of dicationic species via ionization of diols is described. The method makes use of milder reagents at room temperatures, an advantage over use of Magic Acid at -78 °C. A series of mono- and dications were synthesized successfully, including previously unattainable species.

Fluorenyl Cations: Synthesis and Reactivity

“…[9] Mills generated a phenyl-bridged variant of 1Rin +2 , namely 1PhIn +2 , by reaction of the diol with with fluorosulfuric acid, trifluoroacetic anhydride, NaPF 6 , and SO 2 Cl 2 in acetone-d 6 at −78 °C that was characterized by 1 H NMR spectroscopy at −50 °C (Scheme 11g). [42] 1.…”

Fluorenyl Cations: Synthesis and Reactivity

“…[9] Mills generated a phenyl-bridged variant of 1Rin +2 , namely 1PhIn +2 , by reaction of the diol with with fluorosulfuric acid, trifluoroacetic anhydride, NaPF 6 , and SO 2 Cl 2 in acetone-d 6 at −78 °C that was characterized by 1 H NMR spectroscopy at −50 °C (Scheme 11g). [42] 1.…”

Superelectrophiles: Recent Advances

“…The fluorenyl cation itself is expected to be a reactive cation due to its weak anti-aromatic character. Mills and coworkers examined the first dicationic fluorenyl cations and noted their instability [ 26 , 27 , 28 ]. Our group developed an efficient route to 9,9-diarylfluorenes through a superacid-promoted cyclization ( Scheme 7 ) [ 29 , 30 ].…”

Scalable synthesis of quaterrylene: solution-phase 1H NMR spectroscopy of its oxidative dication

“…26 Our product was further characterized as quaterrylene by a novel NMR technique. The well-known insolubility of high melting crystalline substances such as 4 suggests that NMR spectral characterization should be impossible; however, many arenium ions and arene oxidative dications 38,39 (neutral structure minus two electrons) have been observed in solution [40][41][42][43][44][45][46][47] and we investigated whether protonation might increase solubility and facilitate NMR analysis. Quaterrylene ( 4) is insoluble in dichloroethane (DCE), but with the aid of mild sonication (Scheme 2), we find that small amounts dissolve in 1 M triflic acid-d/DCE-d 4 with formation of a dark blue-green solution.…”

Fluorenyl Cations: Synthesis and Reactivity

“…[9] Mills generated a phenyl-bridged variant of 1Rin +2 , namely 1PhIn +2 , by reaction of the diol with with fluorosulfuric acid, trifluoroacetic anhydride, NaPF 6 , and SO 2 Cl 2 in acetone-d 6 at −78 °C that was characterized by 1 H NMR spectroscopy at −50 °C (Scheme 11g). [42] 1.…”

Superelectrophiles: Recent Advances

“…The fluorenyl cation itself is expected to be a reactive cation due to its weak anti-aromatic character. Mills and coworkers examined the first dicationic fluorenyl cations and noted their instability [ 26 , 27 , 28 ]. Our group developed an efficient route to 9,9-diarylfluorenes through a superacid-promoted cyclization ( Scheme 7 ) [ 29 , 30 ].…”

Scalable synthesis of quaterrylene: solution-phase 1H NMR spectroscopy of its oxidative dication

“…26 Our product was further characterized as quaterrylene by a novel NMR technique. The well-known insolubility of high melting crystalline substances such as 4 suggests that NMR spectral characterization should be impossible; however, many arenium ions and arene oxidative dications 38,39 (neutral structure minus two electrons) have been observed in solution [40][41][42][43][44][45][46][47] and we investigated whether protonation might increase solubility and facilitate NMR analysis. Quaterrylene ( 4) is insoluble in dichloroethane (DCE), but with the aid of mild sonication (Scheme 2), we find that small amounts dissolve in 1 M triflic acid-d/DCE-d 4 with formation of a dark blue-green solution.…”

Fluorenyl Cations: Synthesis and Reactivity

“…[9] Mills generated a phenyl-bridged variant of 1Rin +2 , namely 1PhIn +2 , by reaction of the diol with with fluorosulfuric acid, trifluoroacetic anhydride, NaPF 6 , and SO 2 Cl 2 in acetone-d 6 at −78 °C that was characterized by 1 H NMR spectroscopy at −50 °C (Scheme 11g). [42] 1.…”

Superelectrophiles: Recent Advances

“…The fluorenyl cation itself is expected to be a reactive cation due to its weak anti-aromatic character. Mills and coworkers examined the first dicationic fluorenyl cations and noted their instability [ 26 , 27 , 28 ]. Our group developed an efficient route to 9,9-diarylfluorenes through a superacid-promoted cyclization ( Scheme 7 ) [ 29 , 30 ].…”

Scalable synthesis of quaterrylene: solution-phase 1H NMR spectroscopy of its oxidative dication

“…26 Our product was further characterized as quaterrylene by a novel NMR technique. The well-known insolubility of high melting crystalline substances such as 4 suggests that NMR spectral characterization should be impossible; however, many arenium ions and arene oxidative dications 38,39 (neutral structure minus two electrons) have been observed in solution [40][41][42][43][44][45][46][47] and we investigated whether protonation might increase solubility and facilitate NMR analysis. Quaterrylene ( 4) is insoluble in dichloroethane (DCE), but with the aid of mild sonication (Scheme 2), we find that small amounts dissolve in 1 M triflic acid-d/DCE-d 4 with formation of a dark blue-green solution.…”