A Brønsted acid differentiated metal catalyzed hydrogenation has been developed. A combinatorial variation of chiral triflylamides with achiral metal complexes results in a highly active catalyst for the asymmetric reduction.

A mild and efficient method has been developed for the preparation of substituted coumarins from reaction of various phenols with different β-ketoesters via Pechmann condensation in the presence of Brønsted acidic ionic liquid (N-(4-sulfonic acid) butyl triethylammonium hydrogen sulfate) as an effective catalyst under solvent-free conditions. Different phenols reacted with ethyl acetoacetate to...

While a variety of protocols, including traditional enzymatic or non-enzymatic kinetic resolutions, and organicmoleculeor metal-mediated asymmetric transformations have been described, the direct asymmetric reduction of prochiral indole precursors would be one of the most straightforward ways to make chiral indolines. Thus, a few transition metal/chiral phosphine complexes, including Rh, Ru, an...

The Brønsted acid ionic liquid [PyN(CH2)4SO3H][p-CH3PhSO3] has been reported as an efficient catalyst for the Michael addition reaction of indoles to α,βunsaturated ketones. Satisfactory results were obtained, with excellent yields and a simple experimental procedure. The catalyst could be recycled and reused up to three times without any noticeable decrease in the catalytic activity.

A mild and efficient method has been developed for the preparation of substituted coumarins from reaction of various phenols with different β-ketoesters via Pechmann condensation in the presence of Brønsted acidic ionic liquid (N-(4-sulfonic acid) butyl triethylammonium hydrogen sulfate) as an effective catalyst under solvent-free conditions. Different phenols reacted with ethyl acetoacetate to...

phospho sulfonic acid (psa) synthesized as an environmentally safe and efficient solid acid catalyst, and it used for the synthesis of several 2-disubstituted benzimidazoles, 2-substituted benzoxazoles, and 2-substituted quinoxalines in ethanol as a green solvent at ambient temperature is described. (i) a very simple, green and efficient procedure for the synthesis of benzimidazole and also benz...

Zr-containing UiO-66 and MOF-808 are evaluated for converting levulinic acid (LA) into γ-valerolactone (GVL) through various routes: (i) Step-wise esterification of LA to n-butyl levulinate (nBuL) Meerwein-Ponndorf-Verley (MPV) reduction GVL; (ii) One-pot two-steps with n-butanol followed by MPV sec-butanol; (iii) direct conversion GVL a tandem reaction. Selection this multistep complex reactio...

We found an effective catalytic consortium capable of converting glucose to 5-hydroxymethylfurfural (HMF) in high yields (50%). The reaction consists a Lewis acid (NbCl5) and Brønsted (p-sulfonic calix[4]arene (CX4SO3H)), microwave-assisted reactor biphasic system. best result for the conversion HMF (yield 50%) was obtained with CX4SO3H/NbCl5 (5 wt%/7.5 wt%), using water/NaCl MIBK (1:3), at 150...

The first enantioselective synthesis of 4-aza-podophyllotoxin derivatives by partial transfer hydrogenation of lactone-fused quinolines was achieved using a chiral Brønsted acid catalyst. This reaction was extended to a large scope of substrates with good yields and enantioselectivities.