Microporous H-ZSM-5 containing one Brønsted acid site per asymmetric unit is deliberately chosen to host pyridine, methanol, and ammonia as guest molecules. By using new-generation in situ synchrotron X-ray powder diffraction combined with Rietveld refinement, the slight but significant alteration in scattering parameters of framework atoms modified by the guest molecules enables the user to el...

Brønsted acidic ionic liquid triethylamine-bonded sulfonic acid {[Et3N-SO3H]Cl} efficiently catalyzes the one-pot multi-component condensation of 2-naphthol with arylaldehydes and dimedone (5,5-dimethylcyclohexane-1,3-dione) under solvent-free conditions to afford 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-ones in high yields and relatively short reaction times.

A resplendent trio: Protic ionic liquids (PILs) with nucleophilic anions served in concert as regenerable reaction medium, Brønsted acid, and a source of nucleophile. Heating donor–acceptor cyclopropanes 1-methylimidazolium thiocyanate (B:⋅HNCS) afforded products formal (3+2)- (4+2)-cycloaddition isothiocyanic acid.

The strong Brønsted and Lewis acid sites are active in the tandem conversion of levulinic into ethyl valerate. intrinsic activity former is more significant Pd/HBEA catalyst deactivation partially reversible by calcination.

A simple titration technique utilizing pyridine as a FTIR spectroscopy probe is demonstrated to successfully predict relative Brønsted acid-limited reaction rates in different ionic liquid (IL) environments. Relative acidity is shown to vary across three aprotic ILs in a manner that is specific to the particular acid-IL pairing.

Nitrogen heterocycles are ubiquitous in natural products and pharmaceuticals. Herein, we disclose a nitrogen complexation strategy that employs a strong Brønsted acid (HBF4) or an azaphilic Lewis acid (BF3) to enable remote, non-directed C(sp(3))-H oxidations of tertiary, secondary, and primary amine- and pyridine-containing molecules with tunable iron catalysts. Imides resist oxidation and pro...

Transition metal free Brønsted acid mediated synthesis of biologically important pyrido[1,2-a]indole scaffolds through aza-Nazarov type cyclization of readily available diaryl(2-pyridyl)methanol using formic acid has been developed. This methodology has been successfully extended to synthesize atropisomers.

Framework-associated aluminum is demonstrated to facilitate a reversible switch between Lewis and Brønsted acidity in zeolites with the acid sites preferentially populating side-pockets case of mordenite.

Highly enantioselective protonation of α-halo and alkoxy carboxylic acid-derived ketene disilyl acetals is achieved by using P-spiro chiral diaminodioxaphosphonium barfate as a Brønsted acid catalyst, where the enantiofacial discrimination by the catalyst mainly stems from the recognition of the electronic difference between two substituents on the ketene disilyl acetal.