395-24-4

Upstream product

• 6175-14-0 1,1-bis-(4-fluorophenyl)ethene 
• 1178546-41-2 (1-tert-butylcyclohexa-2,5-dien-1-yl)benzene 
• 339-26-4 1,1-bis-(4-fluoro-phenyl)-ethanol 
• 345-92-6 4,4'-Difluorobenzophenone 

Downstream Products

• 357925-36-1 1,1-bis(4-fluorophenyl)-1,2-ethanediamine 
• 1154062-97-1 C₂₁H₁₆F₂N₂ 

Relevant academic research and scientific papers

Indium Tribromide-Catalysed Transfer-Hydrogenation: Expanding the Scope of the Hydrogenation and of the Regiodivergent DH or HD Addition to Alkenes

The transfer-hydrogenation as well as the regioselective and regiodivergent addition of H?D from regiospecific deuterated dihydroaromatic compounds to a variety of 1,1-di- and trisubstituted alkenes was realised with InBr3 in dichloro(m)ethane. In comparison with the previously reported BF3?Et2O-catalysed process, electron-deficient aryl-substituents can be applied reliably and thereby several restrictions could be lifted, and new types of substrates could be transformed successfully in hydrodeuterogenation as well as deuterohydrogenation transfer-hydrogenation reactions.

Synthesis of [1]benzothiopheno[2,3-b][1]benzothiophene derivatives through iodine-mediated sulfuration reaction of 1,1-diarylethylenes

Acceleration of the reaction for the synthesis of [1]benzothiopheno[2,3-b][1]benzothiophenes (BTBTs) from 1,1-diarylethylenes was accomplished by the addition of molecular iodine. Postulated intermediates 3-arylbenzo[b]thiophenes were also selectively prepared by simply changing the amount of iodine and the reaction time.

3-tert-Butyl-Substituted Cyclohexa-1,4-dienes as Isobutane Equivalents in the B(C6F5)3-Catalyzed Transfer Hydro-tert-Butylation of Alkenes

Cyclohexa-1,4-dienes with a tert-butyl group at C3 are shown to function as isobutane equivalents when activated by the strong boron Lewis acid tris(pentafluorophenyl)borane. The hitherto unprecedented transfer hydro-tert-butylation from one unsaturated hydrocarbon to another is achieved with 1,1-diarylalkenes as substrates, thereby presenting itself as a new way of incorporating tertiary alkyl groups into carbon frameworks. Transient carbocation intermediates give rise to competing reaction pathways that could not be fully suppressed.

Cyclohexa-1,3-diene-based dihydrogen and hydrosilane surrogates in B(C6F5)3-catalysed transfer processes

The cyclohexa-1,3-diene motif is introduced as an equally effective alternative to the cyclohexa-1,4-diene platform in B(C6F5)3-catalysed transfer processes. The transfer hydrogenation of alkenes is realised with α-terpinene and the related transfer hydrosilylation is achieved with 5-trimethylsilyl-substituted cyclohexa-1,3-diene. Both yields and substrate scope are comparable with the prior systems.

Br?nsted Acid-Catalyzed Transfer Hydrogenation of Imines and Alkenes Using Cyclohexa-1,4-dienes as Dihydrogen Surrogates

Cyclohexa-1,4-dienes are introduced to Br?nsted acid-catalyzed transfer hydrogenation as an alternative to the widely used Hantzsch dihydropyridines. While these hydrocarbon-based dihydrogen surrogates do offer little advantage over established protocols in imine reduction as well as reductive amination, their use enables the previously unprecedented transfer hydrogenation of structurally and electronically unbiased 1,1-di- and trisubstituted alkenes. The mild procedure requires 5.0 mol % of Tf2NH, but the less acidic sulfonic acids TfOH and TsOH work equally well.

B(C6F5)3-Catalyzed Transfer of Dihydrogen from One Unsaturated Hydrocarbon to Another

A transition-metal-free transfer hydrogenation of 1,1-disubstituted alkenes with cyclohexa-1,4-dienes as the formal source of dihydrogen is reported. The process is initiated by B(C6F5)3-mediated hydride abstraction from the dihydrogen surrogate, forming a Bronsted acidic Wheland complex and [HB(C6F5)3]-. A sequence of proton and hydride transfers onto the alkene substrate then yields the alkane. Although several carbenium ion intermediates are involved, competing reaction channels, such as dihydrogen release and cationic dimerization of reactants, are largely suppressed by the use of a cyclohexa-1,4-diene with methyl groups at the C1 and C5 as well as at the C3 position, the site of hydride abstraction. The alkene concentration is another crucial factor. The various reaction pathways were computationally analyzed, leading to a mechanistic picture that is in full agreement with the experimental observations.

Activation conditions play a key role in the activity of zeolite CaY: NMR and product studies of Bronsted acidity

CaY, activated under different conditions, was characterized with 1H, 31P, and 1H/27A] double resonance MAS NMR. The 1H MAS NMR spectra of CaY, calcined in an oven at 500 °C, shows resonances from H2O (bound to Ca2+ and the zeolite framework), CaOH+, aluminum hydroxides, silanols, and Bronsted acid sites. No evidence for Lewis acidity is observed on adsorption of trimethylphosphine, and an estimate of ≈16 Bronsted acid sites per unit cell is obtained for this sample. CaY activated in an oven at higher temperatures contains less water, but all the other species are still present. In contrast, CaY activated by slow ramping of the temperature under vacuum to 500 or 600 °C shows a much lower concentration of Bronsted acid sites (1/unit cell). Again, no evidence for Lewis acidity was observed. These NMR results have been utilized to understand the very different product distributions that are observed for reactions of 1,1- and 1,2-diarylethylenes in zeolite CaY activated in an oven (in air) and under vacuum. Samples with high concentrations of Bronsted acid sites react stoichiometrically with these sites, yielding diarylalkanes. At low concentrations, the Bronsted acid sites can act catalytically resulting in isomerization reactions.