Biocatalytical access to amides

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The Development of Enzymes for the Preparation of Chemicals

The use of enzymes as catalysts for the preparation of novel organic molecules is becoming more widespread every year. The science of biotransformation has matured, and biocatalysts now stand alongside other forms of catalysts to be considered as viable options for the promotion of a particular reaction. Of great importance for the breakthrough of biocatalysts was the availability of enzymes and the increasing demand for enantiomerically pure compounds. Especially, hydrolytic enzymes, lyases, and oxidoreductases are of technical importance today. The potential of enzymes for the synthesis of chemical compounds is by no means exhausted, and the enormous diversity of microorganisms is an almost unlimited pool for new enzymes. In this paper, different strategies are discussed to find and develop new enzymes for the application in organic synthesis

Enantioselective olefin epoxidation using novel biphenyl and binaphthyl azepines and azepinium salts

Homologous biphenyl and (diastereomeric) binaphthyl tertiary azepines and quaternary iminium salts were prepared from (S)- and (R)-3,3-dimethylbutan-2-amine. Both the amines and iminium ions behave as effective catalysts for the enantioselective epoxidation of unfunctionalized olefins (ee up to 87%)

Practical, solvent-free, one-pot synthesis of C2-symmetrical secondary amines

A novel one-pot reductive amination of ketones using the combination Ti(OiPr)4/H2/Pd–C is reported. This practical procedure does not require any solvent, and affords C2-symmetrical secondary amines in high yields and excellent diastereoselectivities. A novel one-pot reductive amination of ketones using the combination Ti(OiPr)4/H2/Pd–C is reported. This practical procedure does not require any solvent and affords C2-symmetrical secondary amines in high yields and excellent diastereoselectivities

Biphasic Enantioselective Olefin Epoxidation Using Tropos Dibenzoazepinium Catalysts

Several novel chiral iminium TRISPHAT [tris(tetrachlorobenzenediolato)phosphate(V)] salts combining a diphenylazepinium core, chiral exocyclic appendages, and lipophilic counterions have been prepared and tested in biphasic enantioselective olefin epoxidation conditions. Interestingly, the iminium salts derived from commercially available (S)- or (R)-1,2,2-trimethylpropylamine can display efficiency similar to those made from L-acetonamine. Variable-temperature NMR spectroscopy (VT-NMR) and circular dichroism (CD) experiments were performed in search of a correlation between good enantioselectivity in the products and high diastereomeric control of the biphenyl axial chirality of the catalysts

Phosphoramidite Ligands in Iridium-Catalyzed Allylic Substitution

A new phosphoramidite ligand was used in the iridium-catalyzed allylic substitution reaction. This permitted high regio- and enantioselectivities on a wide variety of substrates and nucleophiles. Because of the stereospecificity of the reaction obtained by using branched substrates, a kinetic resolution reaction was attempted. The origin of the impressive efficiency of this ligand in terms of kinetics was explored in detail, as was the role of the substituent in the ortho-position of the amine moiety

Method for the production of primary amines

The present invention relates to a novel enzymatically catalyzed method for the production of aliphatic primary amines, which method comprises the enzymatic oxidation of a primary aliphatic alcohol catalyzed by an alcohol dehydrogenase, amination of the resulting oxocompound catalyzed by a transaminase and optionally coupled with an enzymatically catalyzed regeneration of the consumed cofactor; recombinant expression systems and microorganisms procuring the required enzyme activities; and bioreactors for performing such methods; as well as the use of the obtained amines in organic synthesis, in particular for preparing organic polymers