The acid catalysis of the mutarotation mechanism in the two aldotetroses, d-erythrose and d-threose, has been studied at B3LYP/6-311++G(d,p) computational level in gas phase and in solution employing the PCM-water model. The open-chain, the furanose and the connecting TS structures have been characterized. To study the enhancing effect of acid groups on the electrophilicity of the carbonyl carb...

The response matrix, as metal oxide nanostructure decorated n-type semiconductor interfaces are modified in situ through direct amination and through treatment with organic sulfides and thiols, is demonstrated. Nanostructured TiO₂, SnOx, NiO and CuxO (x = 1,2), in order of decreasing Lewis acidity, are deposited to a porous silicon interface to direct a dominant electron transduction process fo...

In this research, a Brønsted acidic ionic liquid namely N1,N1,N2,N2-tetramethyl-N1,N2-bis(sulfo)ethane-1,2-diaminium chloride {[TMBSED][Cl]2} was employed as a highly efficient catalyst for the solvent-free production of some nitrogen- and oxygen-containing heterocyclic compounds including: (i) polyhydroquinolines (from arylaldehydes, dimedone, β-ketoesters and ammonium acetate), (ii) 3,4-dihyd...

The reductive amination of aromatic aldehydes and amines, performed in the Brønsted acidic ionic liquid [Et3NH][HSO4], using sodium borohydride as a reducing agent is reported. In this protocol, plays crucial role efficiently converting to amines excellent yields, without formation side products. presence imine was generated situ from reaction between underwent smooth reduction with borohydride...

Since the innovative work of Terada and Akiyama, asymmetric reaction using chiral Brønsted acid has attracted great attention. Asymmetric aldol reactions are extensively studied in different organocatalysis. acid-catalyzed may be carried out directly without modification substrates or Mukaiyama type silyl enol ether as nucleophiles. The proceed through formation intermediate followed by attack ...

This report discloses a mild and efficient O-acetylation using easily accessible TMSOAc as novel acetyl reagent O-trimethylsilylation HMDS for various alcohols catalyzed by tunable Brønsted acidic ionic liquids (TBAILs). Imidazolium-based TBAILs were prepared two-step atom-economic reaction acidities measured UV-visible spectroscopy. Both protections accomplished at room temperature with good t...

The catalytic behavior of Brønsted acid sites in three acidic zeolite materials (one MWW and two MFI zeolites) containing dual meso-/microporosity was studied using ethanol dehydration and monomolecular conversion of propane and isobutane as probe reactions. The meso-/microporous MWW zeolite, MCM-36 or pillared MWW, consists of a zeolitic layer structure, with independent microporosity and meso...

Lower Lewis acidity boranes demonstrate greater tolerance to combinations of water/strong Brønsted bases than B(C6 F5 )3 , this enables Si-H bond activation by a frustrated Lewis pair (FLP) mechanism to proceed in the presence of H2 O/alkylamines. Specifically, BPh3 has improved water tolerance in the presence of alkylamines as the Brønsted acidic adduct H2 O-BPh3 does not undergo irreversible ...