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The combined NMR and quantum chemical study of tellurium solution in trioctylphosphine, for the first time, revealed the new unexpected P−Te species. The observed intermediates are absolutely different from the species forming in the reaction of trialkylphosphines with chalcogens up in the group. This finding sheds new light on the mechanism of telluride nanocrystals formation and allow to rationalize the application of this key tellurium precursor in the synthesis of nanostructures. The studied solution was applied in the synthesis of HgTe colloidal quantum dots. [ABSTRACT FROM AUTHOR]

The preparation of the enantiomerically pure (R,R)-lactide (>99%ee) on the gram scale by alcoholysis of rac-lactide in the presence of Amano lipase PS is described. The synthesis of enantiopure lactide by this method is advantageous over traditional preparation via thermal tin-catalysed cyclisation of corresponding oligolactic acids, since the reaction temperature are much lower. That results that no meso-lactide is formed. The alcoholysis of rac-lactide with n-BuOH was studied in the presence of various enzymes in different solvent systems. The kinetic study of the alcoholysis of rac-lactide in the presence of CALB was performed. [ABSTRACT FROM AUTHOR]

A study on the influence of acidic and non-acidic promoters for Pd(PPh3)-catalyzed methoxycarbonylation of vinyl acetate was conducted in order to find an efficient protocol for the synthesis of methyl O-acetyl lactate. Besides known promoters also some new catalytic systems were tested. Aluminium triflate is the most active additive. [ABSTRACT FROM AUTHOR]

The preparation of racemic or enantioenriched propane-1,2-diol from dilactides, oligolactides, or poly-L-lactic acid (PLLA) is described. The transformation is carried out as tandem reactions in MeOH, covering hydrolysis and subsequent hydrogenation by using copper chromite as a catalyst. The starting material present undesired side products of the PLLA synthesis or PLLA waste., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Three sets of new and related chiral phospholane and phosphepine ligands have been prepared for Rh-catalyzed enantioselective hydrogenation. The size and substitution pattern of the cyclic monophosphanes were varied. More importantly, the ligands differ in the nature of the heterocyclic group linked to the trivalent phosphorus atom: 2-pyridone or 2-alkoxypyridine. In the corresponding Rh complexes, the pyridone units of two monodentate P ligands can assemble by hydrogen bonding and form chelates. In contrast, synthetic precursors bearing alkoxypyridine appendages are not able to aggregate via intramolecular hydrogen bonds. The nature of self-assembly is dependent on the nature of the P ligand and the solvent used for the hydrogenation (CH2Cl2 vs. MeOH). These features affect the rate of the reaction as well as the enantioselectivity, which varied in the range of 0-99 % ee Complexation studies and DFT calculations were performed to explain these differences.