New optically active aminoalcohols have been prepared from CeCl3-activated (+)-camphor and (-)-fenchone and N-functionalized organolithium compounds. The aminoalcohols obtained catalyze the addition of diethylzinc to benzaldehyde in high yields and enantioselectivities up to 64%. (C) 1997 Elsevier Science Ltd.

The allylic and homoallylic alcohols 1-8, prepared from (+)-camphor and (-)-fenchone, were ozonized in Et2O at -78 and treated with Et3N or LiAlH4 to give the chiral hydroxy carbonyl compounds 9-16 and the diols 17-24, respectively (Scheme I). In the case of the diols 19 and WI the formation of new chiral centers proceeded with high diastereoselectivity. These diols were prepared highly diastereoselectively also by LiAlH4 reduction of the hydroxy carbonyl compounds 11 and 16a, respectively (Scheme 2). The absolute configuration of the new chiral centers in 19 and 24 was determined by X-ray and NMR methods. The ozonization of compounds 2, 3, 7, and 8 provided the relatively stable hydroxy-substituted 1,2,4-trioxolane derivatives (ozonides) 37-40 (Scheme 5) which were characterized by H-1- and C-13-NMR spectra. ESI-MS, and natural-abundance O-17-NMR spectra.

New axially chiral steroidal binaphthols, prepared from estrone, were applied in the form of their Ti-alkoxides as catalysts for the addition of diethylzinc to aldehydes. The addition reactions proceeded with high yields and enantioselectivities up to 86%. (C) 2000 Elsevier Science Ltd. All rights reserved.

Detailed investigation of the tautomerism of oxazolidines, thiazolidines and selenazolidines substituted at positions 2 and 4 by hydroxy and amino groups was carried out by calculations at HF and MP2 levels of theory and NMR spectroscopy. The relative stabilities of the tautomers of the heterocycles were calculated in gas phase and in solvents CHCl3 and DMSO utilizing the PCM method. The ab initio calculations, in agreement with the available experimental data, predict that the azolidines substituted at positions 2 and 4 by a hydroxy and an amino group exist as amino form in solution, while 2,4-diamino-oxazolidine, -thiazolidine and -selenazolidine occur as mixtures of tautomers.

New 4-substituted benzyl esters of 16-mereaptohexadecanoic acid were prepared by developing a practicable synthetic procedure and using readily available starting materials. The compounds synthesized have been characterized by NMR, MS, IR spectra and elemental analysis. The mercapto derivatives are precursors for the formation of self-assembled monolayers on metal substrates. (C) Central European Science Journals. All rights reserved.

In recent years, impressive progress has been made in the development of new chiral ligands and in new methodology for Zn-mediated enantioselective additions to aldehydes. The current report aims to present the recent progress in this field.

The structures of some 2-substituted indan-1,3-diones are investigated in the gas phase and solution using quantum chemical calculations and spectral (NMR, IR, and UV) measurements. The influence of the substituent at the 2-position on the tautomeric equilibrium of 2-substituted indan-1,3-diones in solvents with different polarity is evaluated. It is shown that the equilibrium in 2-formyl-indan-1,3-dione and 2-acetyl-indan-1,3dione is shifted to the 2-hydroxyalkylidene-indan-1,3-dione tautomer, while 2-carboxyamide-indan-1,3-dione exists as a mixture of two tautomers, 2-(hydroxyaminomethylidene)-indan-1,3-dione and 2-carboamide-lhydroxy-3-oxo-indan, with extremely fast proton transfer between them. The situation for 2-carboxy-indan1,3-dione is quite different -on the basis of the analysis of the obtained results, the possible existence of an anionic form of 2-carboxy-indan-1,3-dione in solution can be inferred.

Self-assembled monolayers (SAM) from para-substituted benzyl-16-mercaptohexadecanoates (R = -Cl; -OCH3; -NO2; -CN) were prepared using standard deposition procedures on silver substrates. The substituents were attached to the terminal benzyl group of the SAM precursor molecules in order to modify the properties of the outer film surface and to probe their influence on the organizational order of the monolayers. The SAMs were characterized by infrared spectroscopic ellipsometry and contact angle measurements. The carbonyl stretching as well as the methylene symmetric and antisymmetric stretching vibrations were employed to determine the tilt angle of the methylene chains. The water advancing contact angles implied that the wetting of the film's outermost surface is substantially different from that expected for more polar groups like NO2, CN and OCH3 and is much closer to that reported for aryl terminated SAMs. The flexible methylene linkage can facilitate the free rotation around C-Ph bond that leads to a specific orientation of the terminal phenyl rings in which they are closely exposed to the interface. An attempt was made to qualitatively characterize the phenyl ring orientations of the different SAMs using the IR spectroscopic ellipsometry data and IR absorption spectra of the same molecules. (C) 2007 Elsevier B.V. All rights reserved.

Monolayers from para-substituted benzyl esters of 16-mercaptohexadecanoic acid (R = -Cl; -OCH3) self-assembled on (111)-textured gold films have been studied in detail with infrared and visible spectroscopic ellipsometry and contact angles measurements. The experimental data testify that these monolayers on gold tend to adopt tilt angles smaller than typical for n-alkanethiols, while the orientation of the phenyl rings is almost perpendicular to the surface. The same precursor molecules self-assembled on silver showed arrangement of the aliphatic chains characteristic for long-chain alkanethiols but differently tilted orientation of the terminal phenyl rings. An attempt was made to explain that different behavior with the different surface energetics of gold and silver substrates.