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...

An enantioselective four-component reaction of a diazoketone, water, an aniline and ethyl glyoxylate in the presence of catalytic Rh2(OAc)4 and a chiral Brønsted acid was developed to efficiently produce β-hydroxy-α-amino acid derivatives in good yields with high diastereoselectivity and enantioselectivity.

A highly enantioselective trapping of protic phosphoramidate ammonium ylides with α-imino esters is reported. The intriguing Rh2(OAc)4 and chiral Brønsted acid co-catalyzed three-component Mannich-type reaction of a diazo compound, a phosphoramidate, and an α-imino ester provides a rapid and efficient access to 2,3-diaminosuccinic acid derivatives with a high level control of diastereo- and ena...

This review focuses on the development of acid catalysis for selective organic transformations conducted in our laboratories for the past 30 years. Several important concepts in designing of catalysts are described with some examples. Further, recent developments in super Brønsted acid and their applications in a one-pot procedure to construct complex molecules with high diastereoselectivities ...

The catalytic enantioselective allylation of aldehydes is a long-standing problem of considerable interest to the chemical community. We disclose a new high-yielding and highly enantioselective chiral Brønsted acid-catalyzed allylboration of aldehydes. The reaction is shown to be highly general, with a broad substrate scope that covers aryl, heteroaryl, alpha,beta-unsaturated, and aliphatic ald...

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...

Abstract We report a Brønsted acid catalyzed enantioselective silylation of biaryl diols with an allylsilane as silicon source. This process enables facile access to enantioenriched silyl ethers axial stereogenicity. A control experiment supports mechanism proceeding by desymmetrization followed kinetic resolution.

Dehydration of glucose to 5-hydroxymethylfurfural (HMF) remains a significant problem in the context of the valorization of lignocellulosic biomass. Hydrolysis of WCl6 and NbCl5 leads to precipitation of Nb-containing tungstite (WO3 ⋅H2 O) at low Nb content and mixtures of tungstite and niobic acid at higher Nb content. Tungstite is a promising catalyst for the dehydration of glucose to HMF. Co...