Vasyl Andrushko

Amination of Aliphatic Alcohols and Diols with an Iridium Pincer Catalyst

Catalytic transformation of alcohols to amines is a fundamental transformation in synthetic organic chemistry. Since a variety of amines play an important role as precursors and final products employed in pharmaceuticals such as anticancer agents and DNA alkylators, agrochemicals, flavors and fragrances, cosmetics and toiletries, polymers, dyes, and other fine chemicals, the development of versatile and efficient amination methods is still an area of vital research. In recent years, a number of transition metal-catalyzed reactions for the synthesis of aliphatic and aromatic amines, such as hydroamination of alkenes or alkynes 4] and aryl halides, has been developed. Moreover, N-alkylation with alkyl halides is a well-known procedure, but the use of alkyl halides is undesirable from an environmental point of view, since it generates wasteful salts as byproducts. Another useful approach in the synthesis of amines is the reductive amination of aldehydes and ketones. However, this method requires the use of strong reducing reagents or dangerous hydrogen gas and is not always selective for monoalkylation of primary amines. Catalytic amination of alcohols is an alternative method for the preparation of amines (Scheme 1) and it is attractive from

Highly stereoselective hydrogenations—As key-steps in the total synthesis of statins

Statins are inhibitors of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMG-CoA reductase) and became the standard of care for treatment of hypercholesterolemia because of their efficacy, safety, and long-term benefits. They are administered as diastereo- and enantiomerically pure compounds. We summarize here two new approaches for the total synthesis of the most important representatives, atorvastatin, and rosuvastatin, based on highly stereoselective hydrogenations as key-steps.

Organic carbonates as alternative solvents for asymmetric hydrogenation

Organic carbonates like propylene carbonate (PC) or butylene carbonate (BC) belong to the class of aprotic, highly dipolar solvents (AHD). Interestingly, their potential as solvents for asymmetric catalysis has been overlooked for a long time. The aim of this work is to evaluate organic carbonates and other organic solvents like THF, CH(2)Cl(2), and acetonitrile as well as members of the AHD-family (DMF, DMSO, etc.) as media for homogeneous asymmetric hydrogenation. For this reason cationic Rh-complexes based on chiral phosphine ligands were tested in the hydrogenation of typical benchmark substrates. In several trials, significant advantages of organic carbonates were found. In contrast to DMSO, DMF and acetonitrile, in PC and BC high conversion rates and excellent enantioselectivities were usually observed.

Structure-Energy Relationships in Unsaturated Esters of Carboxylic Acids. Thermochemical Measurements and ab Initio Calculations

Standard molar enthalpies of formation in the gaseous state of a series of alkyl 3-methylbut-2-enoates have been obtained from combustion calorimetry and results from the temperature dependence of the vapor pressure measured by the transpiration method. To verify the experimental data, we have performed ab initio calculations of all compounds. Enthalpies of formation derived from the G3MP2 method are in excellent agreement with the experimental results. Quantitative analysis of strain effects in alkyl 3-methylbut-2-enoates was discussed in terms of deviations of deltafH degrees m(g) from the group additivity rules. Energetics of the cis-trans isomerization of carboxylic acid derivatives was studied using G3MP2 and DFT methods. Values of strain and cis-trans corrections derived in this work provide further improvement on the group-contribution methodology for prediction of the thermodynamic properties of compounds relevant to biodiesel.