Abstract A series of easily prepared Lewis basic ionic liquids were developed for cyclic carbonate synthesis from epoxide and carbon dioxide at low pressure without utilization any organic solvents or additives. Notably, quantitative yields together with excellent selectivity attained when 1,8‐diazabicyclo[5.4.0]undec‐7‐enium chloride ([HDBU]Cl) was used as a catalyst. Furthermore, the catalyst could be recycled over five times appreciable loss catalytic activity. The effects structure...

Abstract A bifunctional cobalt‐salen complex containing a Lewis acidic metal center and quaternary phosphonium salt unit anchored on the ligand effectively catalyzes synthesis of cyclic carbonates from CO 2 epoxides under mild conditions without utilization additional organic solvents or co‐catalysts. The effects various reaction variables catalytic performance were studied in detail indicate an optimized temperature about 100 °C pressure around 4 MPa, although proceeds smoothly even at...

A benzimidazole-based nonheme manganese complex efficiently catalyzes benzylic, aliphatic C–H as well tertiary oxidation with hydrogen peroxide the oxidant in presence of acetic acid additive. 18O labeling experiments suggest reaction may proceed via a high-valent manganese-oxo intermediate.

We report a remarkable Brønsted acid effect in the epoxidation of olefins by nonheme manganese catalysts and aqueous hydrogen peroxide. More specifically, mononuclear complex bearing tetradentate N4 ligand, MnII(Dbp-MCP)(OTf)2 (Dbp-MCP = (1R,2R)-N,N′-dimethyl-N,N′-bis((R)-(3,5-di-tert-butyl-phenyl)-2-pyridinylmethyl)cyclohexane-1,2-diamine; OTf– CF3SO3–), is highly efficient catalyst H2O2 presence H2SO4 (1–3 mol %). The yields epoxide products as well chemo- enantioselectivities increase...

Abstract Chiral bioinspired iron complexes of N 4 ligands based on the ethylenediamine backbone display remarkable levels enantioselectivity for first time in asymmetric epoxidation α,β‐unsaturated ketones using hydrogen peroxide (up to 87% ee ) or peracetic acid as oxidant, respectively. Notablely, isotopic labeling with H 2 18 O strongly demonstrated that there is a reversible water binding step prior generation significant intermediate. Besides, complex [L Fe(III) (μ‐O)(μ‐CH 3 CO )] 3+...

The cycloaddition of propylene oxide and CO2 to form carbonate promoted by a phosphonium salt covalently bound polyethylene glycol (PEG), the transesterification with methanol dimethyl (DMC) mediated PEG-supported K2CO3, were separately investigated. Inorganic base/phosphonium halide-functionalized PEG (K2CO3/BrBu3PPEG6000PBu3Br) was shown be active for DMC synthesis from oxide, under mild reaction conditions, even low pressure (2 bar). effects various variables on activity selectivity...

The first bimagnetic ionic liquid based on Fe and TEMPO with cooperative functionalities not only exhibited strong paramagnetic behaviour at room temperature under an applied magnetic field of 5000 Oe but also proved to be effective catalyst for selective aerobic oxidation aromatic alcohols mild clean conditions.

Abstract An effective catalytic system comprising a 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) functionalized imidazolium salt ([Imim‐TEMPO] + X − ), carboxylic acid substituted ([Imim‐COOH] and sodium nitrite (NaNO 2 ) was developed for the aerobic oxidation of aliphatic, allylic, heterocyclic benzylic alcohols to respective carbonyl compounds with excellent selectivity up >99%, even at ambient conditions. Notably, catalyst could preferentially oxidize primary alcohol aldehyde rather...

Bioinspired manganese complexes based on N4 ligands, with a more rigid, chiral diamine derived from proline and two benzimidazoles, were synthesized applied to epoxidize olefins hydrogen peroxide as clean oxidant. Notably, 60–99 % isolated yields excellent ee values (up 95 %) obtained by using low catalyst loadings (0.01–0.2 mol %; see scheme; F green, S yellow). Detailed facts of importance specialist readers are published "Supporting Information". Such documents peer-reviewed, but not...

An NHPI and ferric nitrate system was developed for efficient oxidation of benzylic methylenes with 1 atm oxygen at 25 °C, providing up to 97% yield.

Bioinspired manganese complexes have emerged as attractive catalysts for a number of selective oxidation reactions over the past several decades. In present study, we report enantioselective spirocyclic compounds with bearing tetradentate N4 ligands and aqueous H2O2 terminal oxidant under mild conditions; tetralone (1a) its derivatives electron-donating -withdrawing substituents are converted to their corresponding chiral β,β′-diketones high yields enantioselectivities. Spirocyclic indanones...

An asymmetric 5-endo chloroetherification of homoallylic alcohols is successfully developed that employs an easily available quaternary ammonium salt derived from cinchonine as a conventional organocatalyst. This approach provides ready access to β-chlorotetrahydrofurans in high enantioselectivities.

Bioinspired manganese and iron complexes bearing nonporphyrinic tetradentate N4 ligands are highly efficient catalysts in asymmetric oxidation reactions by hydrogen peroxide (H2O2), which carboxylic acid is employed as an essential additive to improve product yields stereo-, regio-, enantioselectivities. The metal should possess two cis-binding sites for oxidant (e.g., H2O2) generate high-valent metal-oxo species active oxidants via a "carboxylic acid-assisted" mechanism. In the present...

The manganese complex Mn(S-PMB)(CF3SO3)2 was proven to be highly efficient in the catalytic oxidation of several benzylic and aliphatic secondary alcohols with H2O2 as oxidant acetic acid additive. A maximum turnover number 4700 achieved alcohol oxidation. In addition, Hammett analysis unveiled electrophilic nature this catalyst N4 ligand.

A novel family of bioinspired manganese(II) complexes bearing chiral aminopyridine ligands that possessed additional aromatic groups and strong donating dimethylamino were synthesized characterized. These manganese exhibited efficient improved activities in the asymmetric epoxidation various olefins, such as styrene derivatives (up to 93% ee) with H2O2 oxidant, even a catalytic amount carboxylic acid additive.

A reversible in situ acidic catalytic system comprising recyclable TEMPO functionalized imidazolium salt ([Imim-TEMPO][Cl])/NaNO(2)/CO(2)/H(2)O was developed for selective transformation of a series aliphatic, allylic, heterocyclic, and benzylic alcohols to the respective carbonyl compounds. Notably, avoids any conventional acid can eliminate unwanted byproducts, facilitate reaction, ease separation catalyst product, also provide safe environment oxidation involving oxygen gas.

Abstract The manganese and iron complexes with the tetradentate N ligand (1 R ,2 )‐ , N' ‐dimethyl‐ ‐bis(1‐methyl‐2‐benzimidazolylmethyl)cyclohexane‐1,2‐diamine have been synthesized characterized. crystal structure of complex demonstrates a cis ‐α configuration. Both are active catalysts for asymmetric epoxidation olefins H 2 O as an oxidant acetic acid additive. Up to 96 % ee was observed α,β‐unsaturated ketones at −20 °C.

The highly efficient catalytic oxidation and oxidative kinetic resolution of secondary alcohols has been achieved using mononuclear Mn(<sc>ii</sc>) catalysts H₂O₂.

Herein, a facile, environmental-friendly, and sustainable strategy for efficient separation, conversion, utilization of lignocellulose components was developed. Lignocellulose were separated by green deep eutectic solvent (DES). The extracted lignin had potential downstream production aromatic chemicals used to synthesize lignin-doped carbon dots (CDs) in ratiometric fluorescent probe detecting biogenic amines (BAs) that generated from food spoilage. preparation CDs provided an convert...

Several novel biomass-based ionic liquids derived from 5-hydroxymethylfurfural were used as single-component, recyclable and efficient catalysts for transformation of CO 2 .

A cobalt complex with a tetradentate aminopyridine ligand catalyzes the cycloaddition reactions of CO 2 and epoxides, constituting single-component, efficient solvent-free system.

Ethylene carbonate (EC) as a unique solvent for the Wacker oxidation of higher alkenes and aryl has been successfully developed using molecular oxygen sole oxidant, in which colloidal Pd nanoparticles stabilized EC are considered to facilitate its reoxidation under cocatalyst-free conditions.