Search results for "Catalysis"

ChemInform Abstract: Recyclable Heterogeneous Palladium Catalysts in Pure Water: Sustainable Developments in Suzuki, Heck, Sonogashira and Tsuji-Tros…

2010

This review summarizes the progress made essentially these last ten years on heterogeneous palladium catalysis in pure water. The work covers four important palladium-catalyzed transformations for carbon-carbon bond formation: Suzuki, Heck, Sonogashira and Tsuji-Trost reactions. The discussion focuses on the efficiency and reusability of the heterogeneous catalysts as well as on the experimental conditions from a sustainable chemistry point of view. The review is introduced by a discussion on mechanistic aspects inherent to heterogeneous catalysis.

Renaissance of Electrosynthetic Methods for the Construction of Complex Molecules

2014

Current affairs: Efficient N,N dimerization by using an electric current is a recent powerful example of preparative electrosynthesis where conventional reagents fail. The general and practical nature of this method as well as other applications will breathe new life into the electroorganic synthesis of complex molecules.

Strain Release Chemistry of Photogenerated Small‐Ring Intermediates

2021

Abstract Photochemical processes, such as isomerizations and cycloadditions, have proven to be very useful in the construction of highly strained molecular frameworks. Photoinduced ring strain enables subsequent exergonic reactions which do not require the input of additional chemical energy and provides a variety of attractive synthetic options leading to complex structures. This review covers the progress achieved in the application of sequences combining excitation by ultraviolet light to form strained intermediates, which are further transformed to lower energy products in strain‐release reactions. As ring strain is considerable in small ring systems, photogenerated three‐ and four‐memb…

Cover Feature: New Approach to 1,4-Benzoxazin-3-ones by Electrochemical C−H Amination (Chem. Eur. J. 50/2017)

2017

Front Cover: Iron-Catalyzed C−O Bond Activation: Opportunity for Sustainable Catalysis (ChemSusChem 20/2017)

2017

Imidazolium and Potassium Hydrogen Carbonate Salts as Ecofriendly Organocatalysts for Oxazolidinone Synthesis

2016

International audience; Although oxazolidinones are valuable intermediate compounds for industrial applications, no synthetic method is suitable for their production on a large scale owing to the use of reagents/catalysts that are hazardous or toxic to human health or ecotoxic for the environment. In this manuscript, we describe new and efficient catalysts, that is, the nontoxic hydrogen carbonate anion in combination with a potassium or diisobutylimidazolium ([iBu(2)IM]) countercation, for the conversion of -amino alcohols into cyclic oxazolidinones in high yields of 69 to 90%. Depending on the catalytic conditions, both catalysts could be easily recovered from the crude reaction products …

Progress in palladium-based catalytic systems for the sustainable synthesis of annulated heterocycles: a focus on indole backbones

2012

BIOVERT+LDJ; A survey highlighting the most recent palladium catalytic systems produced and their performances for progress in direct synthesis of indole backbones by heterocarbocyclization of reactive substrates is provided. The discussion is developed in relation with the principles of sustainable chemistry concerning atom and mass economy. In this respect, the general convergent character of the syntheses is of particular interest (one-pot, domino, cascade or tandem reactions), and the substrates accessibility and reactivity, together with the final waste production, are also important. This critical review clearly indicates that the development of ligand chemistry, mainly phosphines and…

Cover Picture: Metal‐ and Reagent‐Free Highly Selective Anodic Cross‐Coupling Reaction of Phenols (Angew. Chem. Int. Ed. 20/2014)

2014

Iron-Catalyzed C−O Bond Activation: Opportunity for Sustainable Catalysis

2017

Oxygen-based electrophiles have emerged as some of the most valuable cross-coupling partners in organic synthesis due to several major strategic and environmental benefits, such as abundance and potential to avoid toxic halide waste. In this context, iron-catalyzed C-O activation/cross-coupling holds particular promise to achieve sustainable catalytic protocols due to its natural abundance, inherent low toxicity, and excellent economic and ecological profile. Recently, tremendous progress has been achieved in the development of new methods for functional-group-tolerant iron-catalyzed cross-coupling reactions by selective C-O cleavage. These methods establish highly attractive alternatives t…

Expanding the Variety of Zirconium‐based Inorganic Building Units for Metal–Organic Frameworks

2019

Two new zirconium-based metal-organic frameworks with the composition [Zr6 O4 (OH)4 (OAc)6 (BDC)3 ] (CAU-26) and [Zr5 O4 (OH)4 (OAc)4 (BDC)2 ] (CAU-27) are reported, which were synthesized from acetic acid, a rarely utilized but green and sustainable solvent (BDC2- : 1,4-benzenedicarboxylate). Structure determination aided by automated electron diffraction tomography revealed that CAU-26 is composed of layers of well-known {Zr6 O8 } clusters interconnected by terephthalate ions. In contrast CAU-27 exhibits a three-dimensional structure with a so far unknown type of one-dimensional inorganic building unit (IBU), which can be rationalized as condensed polyhedron-sharing chains of {Zr6 O8 } cl…