A general asymmetric Strecker-type reaction is reported, catalyzed by the Lewis acid-Lewis base bifunctional catalyst 1. The reaction of trimethylsilyl cyanide (TMSCN) with various fluorenyl imines, including n-aldimines and alpha,beta-unsaturated imines, proceeds with good to excellent enantioselectivities in the presence of a catalytic amount of phenol as additive (20 mol%) (catalytic system ...

An approach for the control and understanding of supported molecular catalysts is demonstrated with the design and synthesis of open and closed variants of a grafted Lewis acid active site, consisting of Al(III)-calix[4]arene complexes on the surface of silica. The calixarene acts as a molecular template that enforces open and closed resting-state coordination geometries surrounding the metal a...

A catalytic asymmetric procedure for the preparation of beta-amino acids (specifically beta-substituted aspartic acid derivatives) is reported. The cinchona alkaloid catalyst benzoylquinine (BQ) mediates up to five distinct steps of a reaction pathway, all in one reaction vessel. The products of this reaction, highly optically enriched beta-substituted aspartic acid derivatives, were prepared f...

A high yielding rearrangement of epoxy-esters, under Lewis acid conditions, to give bicyclic ortho esters is reported.

The synthesis of a range of fluorinated heterocycles is described via a Lewis acid-mediated Prins-type cyclisation.

Hydrogen production by metal particles in water could provide a renewable energy cycle, if its reaction kinetics is accelerated. Here, ab initio molecular dynamics simulation reveals rapid hydrogen production from water by a cluster (or superatom) consisting of a magic number of aluminum atoms, Al{n} (for instance, n=12 or 17). We find a low activation-barrier mechanism, in which a pair of Lewi...

Several commercial Lewis acids, including those of the Bronsted type, specifically HBF(4).OEt(2), are able to catalyze the reaction between aromatic aldehydes and ethyl diazoacetate to produce 3-hydroxy-2-arylacrylic acid ethyl esters and 3-oxo-3-arylpropanoic acid ethyl esters. Reactions catalyzed by the iron Lewis acid [(eta(5)-C(5)H(5))Fe(+)(CO)(2)(THF)]BF(4)(-) (i.e., 1) have the best yield...

The silica boron sulfuric acid nanoparticles (SBSANs) as an efficient heterogeneous solid acid catalyst with both Brønsted and Lewis acidic sites catalyzed the preparation of bis-4-hydroxycoumarin derivatives using reaction of aldehydes and 4-hydroxycoumarin under mild and solvent-free condition at room temperature. This new and efficient methodology has advantages in comparison with currently ...

We have reported the fabrication of boric acid incorporated into surface of magnetite nanoparticles. The catalyst was characterized using spectroscopic, magnetic and thermal techniques (FT-IR, SEM, XRD, ICP, VSM and TGA). It catalyzed Mukaiyama aldol reaction of a ketene silyl acetal type nucleophile ((1-methoxy-2-methylprop-1-enyloxy) trimethylsilane), and various aldehydes (aromatic, aliphati...

CoSBA-xAl catalysts show a high yield in the levulinic acid conversion into ethyl valerate. This is due to presence of weak Lewis sites associated with Co2+ species that have been stabilized by incorporation Al support.