Silica Vanadic Acid, SVA, (oxo-vanadium has been supported on silica) as a dual Lewis and Bronsted acid ability was prepared and efficiently catalyzed one-pot multi-component condensation of enolizable ketones or alkyl acetoacetates with aromatic aldehydes, acetonitrile and acetyl chloride. The described reaction was produced β-acetamido ketone or ester derivatives in high to excellent yields i...

In the direct Mannich reaction and synthesis of α,β-unsaturated ketones, the use of organobismuth complexes as catalysts leads to high diastereoselectivity and products of single trans conformation. In this paper, we illustrate the relationship between structure and catalytic activity as well as diastereoselectivity of organobismuth complexes having a 5,6,7,12-tetrahydrodibenz [c,f][1,5]thiobis...

This overview paper summarizes the current status of the Lewis acid-base or generalized donor-acceptor concepts and their application to solubility theory and related problems in the fields of surface and colloid chemistry. Simple second-order perturbation theory is then used to evaluate the pros and cons of various empirical treatments or Lewis acid-base strengths currently found in the litera...

TiCl4/nano-cellulose as a biodegradable and eco-friendly Lewis acid catalyst was synthesized via reaction of nano-cellulose and TiCl4. This catalyst was characterized and used for synthesis of asymmetric highly functionalized tetrahydropyridines via a five-component condensation reaction of p-substituted anilines, aldehydes and ethyl acetoacetate under solvent-free condition. Simple methodology...

Piancatelli rearrangement on substituted non-symmetrical furan-2,5-dicarbinols has been developed using an effective combination of microwave activation and Lewis acid catalyst.

The Michael reaction, which involves 1,4-addition of a nucleophile (preferably a C-nucleophile) to an a,b-unsaturated compound, offers a simple yet effective way of making C C bonds, which makes it one of the most widely used reactions in both industry and academia. The reaction, as first reported by Arthur Michael in 1887, involves primarily the attack of a Cnucleophile, generated from compoun...

A set of hierarchical beta zeolites with variable Si/Al ratios, nanoparticle sizes, textural and acidic properties was prepared using a hydrothermal treatment concentrated alkali metal-free protic acid-containing zeolite gel-precursor. The obtained catalysts were investigated in the Prins cyclization isovaleraldehyde isoprenol yielding commercially valuable tetrahydropyranol (Florol). highest y...

Production of 5-hydroxymethylfurfural (HMF) from biomass-derived glucose has great potential for synthesis renewable fuels and chemicals. Selective conversion to requires a balance between Lewis Brønsted acids the cascade isomerization followed by fructose dehydration. A dual Brønsted-Lewis acid, phosphotungstic acid encapsulated MIL-101(Al)–NH2 metal–organic frameworks (MOFs) was developed cat...

TiCl2/nano-γ-Al2O3 as a new heterogeneous Lewis acid catalyst was synthesized and characterized by FE-SEM, XRD, FT-IR, EDS, XRF, BET and TGA. N-substituted pyrroles have been synthesized via Paal–Knorr reaction in the presence of TiCl2/nano-γ-Al2O3 at room temperature under solvent-free conditions.

An asymmetric Lewis acid-mediated [2,3]-sigmatropic rearrangement of allylic amines has been developed, affording the corresponding homoallylic amines in good yield and excellent enantioselectivities. The rearrangement proceeds by complexation of the chiral Lewis acid to the amine followed by deprotonation and rearrangement.