M.V. Livantsov

First enantiopure phosphapalladacycle with planar chirality. X-Ray study of the racemic dimer and (Spl,SCSN)-diastereomer of its prolinate derivative

Abstract The first P , C -cyclopalladated complex with planar chirality was prepared by direct cyclopalladation of prochiral di- tert -butyl(ferrocenylmethyl)phosphine. Resolution of the racemic dimer was achieved through separation of its diastereomeric ( S )-prolinate derivatives. The palladacycle structure was confirmed by the 1 H NMR spectra of the dimer and its triphenylphosphine adduct and an X-ray diffraction study of the racemic dimeric complex. The absolute configuration of the planar chirality was determined by an X-ray diffraction investigation of one of two diastereomers of the ( S )-prolinate derivative.

P*-Chiral phosphapalladacycle as derivatizing agent for enantiomeric purity determination of α-amino acids by means of 31P NMR spectroscopy

Abstract A P*-chiral cyclopalladated complex was shown to be an efficient chiral derivatizing agent for enantiomeric excess determination of α-amino acids by 31 P NMR technique. The main advantages of this type of reagent are discussed.

Asymmetric exchange of cyclopalladated ligands with a high level of asymmetric induction: a new route to optically active phosphapalladacycles

Abstract The first example of an asymmetric Cue5f8H bond activation with chirality transfer (up to 91% ee) from an enantiopure CN -palladacycle is described. This asymmetric version of cyclopalladated ligand exchange was elaborated in an aprotic medium using prochiral phosphines as substrates and an enantiopure benzylaminate palladacycle bearing a primary amino group and a bulky tert -Bu substituent on the side chain as the palladation agent.

FIRST OPTICALLY ACTIVE P*-CHIRAL PHOSPHAPALLADACYCLE

Abstract The first cyclopalladated complex containing an asymmetric P*-donor atom in the phosphapalladacycle has been prepared in an enantiomerically pure state via resolution of diastereomeric (S)-prolinate derivatives of the racemic dimer. The absolute configuration of the P*-stereocenter (SP) and the geometric configuration of the palladium environment (Z) were determined by an X-ray diffraction investigation of the less soluble diastereomer of the (S)-prolinate adduct.

Highly diastereoselective cyclopalladation of α-ferrocenylethylphosphine: X-ray study of the first phosphapalladacycle of planar chirality

Abstract First planar chiral phosphapalladacycle was prepared in diastereomerically pure state via direct cyclopalladation of the di-tert-butyl-1-ferrocenylethylphosphine. The palladacycle structure was confirmed by 1 H NMR spectra; relative configuration of central and planar chirality was determined by an X-ray diffraction study of the triphenylphosphine adduct.

Synthesis of mono-and diphosphorus-substituted proline derivatives containing P–C–N fragments

Convenient methods for the synthesis of new types of mono-and diphosphorus-substituted proline derivatives containing P–C–N fragments were developed based on special pre-prepared proline-containing synthons. The corresponding organophosphorus acids including a proline fragment were also synthesized.

Synthesis of substituted fulvenes with inden-2-ylphosphonic acid fragments

We have developed preparative methods for the synthesis of substituted fulvenes including inden-2-ylphosphonic acid fragments, as well as aromatic and heterocyclic substituents, based on bis(trimethylsilyl)inden-2-ylphosphonate and substituted azomethines in the presence of sodium hydride as an efficient initiator of the reaction. Subsequent treatment of the phosphonates with methanolic solution of sodium methoxide furnished water-soluble disodium salts of the corresponding phosphonic acids.

Five-membered nitrogen containing heterocycle derivatives of mono and diphosphonic acids

A research on ionic liquids, across many varied applications, is strong and still growing area of interest. New chiral imidazolium-based ionic liquids containing (1R,2S,5R)-(–)-menthol substituent, having symmetrical structure of the salts, have been synthesized and characterized. Monocyclic terpen alcohol: (1R,2S,5R)-(–)-menthol, obtained from a variety of mint (Menthae L.), was used as a substrate in two different reactions to obtain 1,3-bis[(1R,2S,5R)-(–)-menthoxymethyl]imidazolium chloride [1], which is a prototype of chiral ionic liquids. After that, metathesis of this symmetrical imidazolium chloride with various organic and inorganic salts in menthol or water/menthol solution was carried out. The ion exchange reaction goes smoothly, with the satisfactory exceed (from 94 to 99%). Discussed symmetrical salts belong to Chiral Ionic Liquids (CILs) where the chirality resides in the cation and is associated with the presence of optical active (1R,2S,5R)-(–)-menthol. Obtained symmetrical salts are hydrophobic, and airand moisture-stable under ambient conditions. Moreover, they are non-volatile and non-flammable. Some of the 1,3-bis[(1R,2S,5R)-(–)-menthoxymethyl]imidazolium salts [i.e.: chloride, bis(trifluoromethanesulfonyl) imide, acesulfame, saccharinate] possess excellent antielectrostatic properties and their ability to drain the surface charge is similar to these of a known antistatic agent (Catanac 609: American Cyanamin Co.).