Trimethylenemethane-Ruthenium(II)-Triphos complexes as highly active catalysts for catalytic C—O bond cleavage reactions of lignin model compounds

Ru ready for it yet? The reaction of [Ru(cod)(methallyl)2] with tripodal phosphine ligands of the TRIPHOS-type results in the formation of Ru-trimethylenemethane complexes. Evaluation of their catalytic properties revealed a high activity for hydrogen transfer and C—O cleavage reactions including the hydrogen-free reductive cleavage of 2-aryloxy-1-arylethanols as model compounds for lignin linkages

Gayya kuyusu

Emine Semiye'nin Dersaadet'te tefrika edilen Gayya Kuyusu adlı roman

The history of Shtokman field development

Let's twist again! The first highly enantioselective asymmetric reaction in which a chiral reaction medium is the sole source of chirality is presented. The aza‐Baylis–Hillman reaction in an ionic liquid with a chiral anion, whose design is based on mechanistic insights, gave products with up to 84 % ee

Enantioselective crystallization using chiral ionic liquids

The resolution of chiral compounds has been of enormous interest to pharmaceutical, agricultural and food industries. The need for efficient techniques for the production of enantiomerically pure compounds is increasing due to the recent high demand for single enantiomers [1]. Resolution of racemates can be realized by using various methods such as kinetic resolution (chemical catalysis and biocatalysis), diastereomeric salts formation, (preparative) chromatography, preferential crystallization, and enantioselective membranes (molecularly imprinted polymeric membranes). In this work, a new approach for chiral separation based on enantioselective crystallization using chiral solvents will be presented. In principle, it is expected that a chiral solvent can create some selective interactions which will enable differentiation between the two single enantiomers. This differentiation can be used for the resolution of racemates. The chiral solvents are classified into two main groups that are a) classical chiral solvents and b) non-classical chiral solvent (ionic liquids and liquid crystals). In literature a few work do exist in the field of classical chiral solvents [2], but none for using chiral ionic liquids for enantioselective crystallization. However, recently Reichert and co-workers reviewed the general possibilities and the potential of ionic liquids as solvents in crystallization processes [3]. The work to be presented is concerned with studying the potential of both classical chiral solvents and chiral ionic liquids in enantioselective crystallization on the example of two selected pharmaceutical model systems. The effect of the used chiral solvent on thermodynamics and crystallization kinetics will be shown. The results obtained for each of the systems will be discussed and comparatively evaluated