Heterogeneous Esterification from α-Hydroxy Ketone and Alcohols through a Tandem Oxidation Process over a Hydrotalcite-Supported Bimetallic Catalyst

Abstract

Heterogeneous aerobic oxidative esterification between α-hydroxy ketone and alcohols catalyzed by a hydrotalcite-supported bimetallic catalyst (CuMn/HT) using O2 as a green oxidant was achieved. Recyclable CuMn/HT exhibits high catalytic activity due to increased content of oxygen vacancies and a newly generated CuMn2O4 crystal phase. This clean esterification proceeds through a tandem oxidation process in the absence of any additives and ligands and affords α-keto esters in good to excellent yields. Moreover, the catalytic system tolerates complicated bioactive molecules as raw materials and can be performed on a multigram scale.

A sustainable preparation of catalytically active and antibacterial cellulose metal nanocompositesviaball milling of cellulose

“…It has already been successfully utilized in the direct synthesis of nanoparticles, [45][46][47][48] functionalization of cellulose, [49][50][51] and preparation of composite catalysts. 52,53 In this study, we show the preparation of cellulose-metal nanocomposites (cellulose-Au, Ag, Pd, Pt, Cu, and Co) by activation of cellulose (cotton and microcrystalline cellulose (MCC)) by cryomilling (Scheme 1). This method uses no reducing and stabilizing agentsonly cellulose, metal ion precursors and a few milliliters of water or acetonitrile (the latter is used only when the metal precursor is not well-soluble in water, and thus can be avoided by using different counter ions etc.…”

Manipulating Activity and Chemoselectivity of a Benzaldehyde Lyase for Efficient Synthesis of α-Hydroxymethyl Ketones and One-Pot Enantio-Complementary Conversion to 1,2-Diols

“…α-Hydroxymethyl ketones are often encountered in the structure of many bioactive products − and are also routinely used as versatile building blocks for the manufacture of high-value important molecules in organic synthesis, with numerous applications as chiral auxiliaries, chiral ligands, or chiral catalysts for asymmetric synthesis (Scheme A). − Several cascade reactions have been established to obtain useful and high-value chemicals with α-hydroxymethyl ketone as an intermediate. − For example, dihydroxyacetone was an important α-hydroxymethyl ketone in the pathway for cell-free starch, hexoses, or l -alanine synthesis. − Owing to its great importance, the development of efficient methods for the synthesis of α-hydroxymethyl ketones is an important research focus in the pharmaceutical industry. The chemical methods for the preparation of α-hydroxymethyl ketones involve iodine-promoted activation, oxidation, and dioxygenation of alkenes, , substitution of α-haloketones, , oxidation of diols, decarboxylative oxidation of carboxylic acids, , and hydroxymethylation of aldehydes by N -heterocyclic carbenes (NHCs). , Compared to conventional chemical methods that often require high toxic and cost reagents, harsh reaction conditions, and sometimes low isolated yields, biocatalysis has become an attractive approach to prepare α-hydroxymethyl ketones.…”

One-Pot Enzymatic–Chemical Cascade Route for Synthesizing Aromatic α-Hydroxy Ketones

“…α-Hydroxy ketones are important compounds used to synthesize a series of natural products and pharmaceuticals − in the field of organic chemistry. Among these compounds, 2-hydroxyacetophenone (2-HAP) is a promising and cost-effective synthetic intermediate widely used as a building block for the synthesis of valuable larger molecules, such as α-ketoesters, syn -amino alcohols, and antitumor Schiff bases. ,− Additionally, 2-HAP is used to prepare optically pure chemicals, such as ( R )- and ( S )-1-phenyl-1,2-ethanediol, which can be used as medicine intermediates and liquid crystal materials, respectively. , …”