The Chemistry of Trialkyloxonium Fluoroborates

Граник, В. Г.; Pyatin, B. M.; Глушков, Р. Г.

doi:10.1070/rc1971v040n09abeh001967

Cited by 34 publications

(17 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These Meerwein salts are excellent alkylating agents for nucleophiles containing heteroatoms but are not capable of C-alkylating aromatic or aliphilic hydrocarbons. 8 When superacids such as FSO 3 H-SbF 5 (magic acid, H o ) -21 to -24) or CF 3 SO 3 H-B(O 3 SCF 3 ) 3 (triflatoboric acid, H o -20 to -21) are added, trialkyloxonium ions (1) alkylate aromatics such as benzene, toluene or chlorobenzene (eq 3). 9 Weaker acids do not effectively catalyze the alkylations.…”

Section: Alkylation With Protosolvated Oxonium Ions and Carbocationsmentioning

confidence: 99%

Superelectrophilic Solvation

2004

View full text Add to dashboard Cite

Nucleophilic solvation is the interaction of electron-donor solvents with electron-deficient reagents. Electrophilic solvation is the related reverse interaction. Superelectrophilic solvation involves the interaction of electron-donating groups (ligands) of overall electron-deficient species (electrophiles) with strongly electron-acceptor superacids. It occurs with liquid superacids, on solid acids, and even in some enzymatic biological systems. Diminishing neighboring group participation of the electrophilic centers by the affected groups greatly enhances their electrophilic reactivities (superelectrophilic activation), resulting in unusual reactions of substantial interest. Representative examples of superelectrophilic solvation are discussed.

show abstract

Section: Alkylation With Protosolvated Oxonium Ions and Carbocationsmentioning

confidence: 99%

Superelectrophilic Solvation

2004

View full text Add to dashboard Cite

show abstract

“…Surprisingly, no significant levels of racemization were observed. Even under conditions that are known to form iminium ions (entries 6, 7, and 8), we were unable to effect the desired epimerization. These results strongly suggest that once the lactam is formed, the C(14) center is completely stable to racemization under acidic conditions.…”

Section: Resultsmentioning

confidence: 86%

Total Synthesis of (−)-Tetrahydropalmatine via Chiral Formamidine Carbanions: Unexpected Behavior with Certain Ortho-Substituted Electrophiles

Matulenko

Meyers

1996

J. Org. Chem.

View full text Add to dashboard Cite

A method has been developed by alkylation of chiral lithioformamidines to construct protoberberine alkaloids with a C(9) and C(10) D-ring substitution pattern. This ring pattern was established using an ortho-substituted hydroxymethylbenzene electrophile protected as a silyl ether to ultimately provide (-)-tetrahydropalmatine in 88% ee. Additionally, we have discovered limitations with ortho-substituted electrophiles in the asymmetric formamidine alkylation. These electrophiles have the potential to disrupt the lithium formamidine chelate and cause the selectivity in the alkylation to be uncharacteristically low. The total synthesis of (+/-)-canadine and (-)-tetrahydropalmatine along with the limitations to the formamidine alkylation technology are delineated herein.

show abstract

“…Subsequently, samples were derivatized with Et 3 O + [BF 4 ] − . This method was previously reported to yield 64% EtSCN after aqueous reaction [25]. In this method, a stable isotopically labeled internal standard (K + [S 13 C 15 N] − ) is added prior to derivatization, which protects against the potential for variations in reaction efficiency A suitable amount of Et 3 O + [BF 4 ] − was dissolved (1 g/ml) in ice-cold ultrapure water in a 15 ml Falcon tube and inverted three times.…”

Section: Methodsmentioning

confidence: 99%

Determination of thiocyanate in exhaled breath condensate

Chandler

Horati

Walker

et al. 2018

Free Radical Biology and Medicine

View full text Add to dashboard Cite

Thiocyanate is a heme peroxidase substrate that scavenges oxidants produced during inflammation and regulates host defense. In cystic fibrosis (CF) patients, increased airway thiocyanate levels are associated with improved lung function. Research on airway thiocyanate is limited, however, because convenient non-invasive airway sampling methods, such as exhaled breath condensate (EBC), yield low concentrations that are difficult to detect with available assays. In the present study, we developed a method for the determination of thiocyanate in dilute samples using isotope dilution headspace gas chromatography-coupled high-resolution, accurate-mass mass spectrometry (GC-HRMS). The method reliably quantified as little as 4 pmol thiocyanate in EBC and could detect even lower amounts. We successfully measured thiocyanate in EBC from seven healthy donors, with a mean ± SD of 27 ± 16 nM and a median inter-assay coefficient of variation of 10.4% over six months. The method was applied to other biological fluids (plasma from the same visit as EBC donation; bronchoalveolar lavage fluid [BALF] from infants with CF; and healthy adult mouse BALF), giving reliable quantification of samples ranging from 10 nM to 100 µM. Thiocyanate concentrations in fluids besides EBC were (from lowest to highest): 0.73 ± 0.39 µM in BALF of healthy adult mice (n = 6); 1.4 ± 1.4 µM in BALF from infants with CF (n = 24); 46 ± 22 µM in the plasma of adult volunteers (n = 7). These results demonstrate the utility of this new method for clinical determination of thiocyanate in EBC and other biological fluids.

show abstract

The Chemistry of Trialkyloxonium Fluoroborates

Cited by 34 publications

References 3 publications

Superelectrophilic Solvation

Superelectrophilic Solvation

Total Synthesis of (−)-Tetrahydropalmatine via Chiral Formamidine Carbanions: Unexpected Behavior with Certain Ortho-Substituted Electrophiles

Determination of thiocyanate in exhaled breath condensate

Contact Info

Product

Resources

About