Jarosław Błaszczyk

A highly efficient asymmetric synthesis of β-aminophosphonic acids, via addition of α-phosphonate carbanions to chiral, enantiopure sulfinimines

Addition of α-phosphonate carbanions to (S)-sulfinimines 1 affords N-sulfinyl β-aminophosphonates 2 in a diastereoisomeric ratio from 5:1 to 10:1; the major diastereoisomers of 2, after separation, are converted to the corresponding β-aminophosphonates 3 or to (+)-β-amino-β-phenylethane phosphonic acid 4, whose absolute configuration was established as (R) by X-ray crystallography.

The synthesis and X-ray structural studies of 2-cholesteryl-2-thio-1,3,2-oxathiaphospholane and 2-cholesteryl-2-thio-1,3,2-dithiaphospholane

Two “thiophospholane” derivatives of cholesterol: 2-cholesteryl-2-thio-1,3,2-oxathiaphospholane (1) and 2-cholesteryl-2-thio-1,3,2-dithiaphospholane (2) were synthesized as new reagents for introducing a cholesteryl moiety at the 5′-end of oligonucleotidesvia the phosphorothioate or phosphorodithioate bond. Compounds1 and2 were subjected to structural studies by X-ray methods. Both compounds crystallized in the orthorhombic system, space group P212121,1 witha=6.283(1) Å,b=12.067(1) Å,c=38.983(3) Å,2 witha=6.371(1) Å,b=11.971(1) Å andc=39.502(3) Å. The five-membered heterocyclic rings of both compounds attain a half-chair conformation in the solid state. In structures of1 and2 a disorder of some atoms is observed. The absolute configuration at the phosphorus atom in1 of the components of diastereoisomeric mixture has been established.

Structure and dynamics of bis(organothiophosphoryl) disulfides in the solid state. X-Ray diffraction and cross-polarization magic angle spinning nuclear magnetic resonance studies

The structure and dynamics of selected bis(organothiophosphoryl) disulfides have been studied by single-crystal X-ray diffraction and high-resolution solid-state NMR spectroscopy. The crystal and molecular structures of bis[tert-butyl(phenyl)thiophosphoryl] disulfide 1, bis-(diphenoxythiophosphoryl) disulfide 2 and bis[tert-butyl(methoxy)thiophosphoryl] disulfide 3 were determined, giving space groups of C2/c, P212121 and P for 1, 2 and 3, respectively. Both phosphorus centres of the disulfide 1 have the same absolute configuration, as have those of the disulfide 3, although their environments were significantly different. It has been unambiguously proved that the S–S disulfide bond length varies as a function of the PSSP torsional angle. Moreover the influence the S–S–PS conformation has on the P–S bond length is discussed. Carbon-13 NMR dipolar-dephasing experiments, using powdered samples, indicated that both the tert-butyl and methoxy groups attached to the phosphorus atom were in a fast regime exchange.

New enantiomeric fluorine-containing derivatives of sulforaphane: Synthesis, absolute configurations and biological activity

Three pairs of enantiomers of the unknown sulforaphane analogs bearing organofluorine substituents bonded to the sulfinyl sulfur atom and having different number of methylene groups in the central carbon chain were synthesized and fully characterized, including determination of their absolute configurations. All the new compounds were tested in vitro for their cytotoxicity against melanoma cells to show increased activity in comparison with the natural sulforaphane. The influence of the particular structural changes in the molecule on the cytotoxicity is discussed.

α-phosphoryl sulfoxides. X. A general synthesis of optically active α-chlorovinyl sulfoxides

Abstract A general and efficient synthesis of enantiomeric α-chlorovinyl p-tolyl sulfoxides 1 using (+)-(S) C (S) S -α-chloro-α-dimethoxyphosphorylmethyl p-tolyl sulfoxide as a key substrate for the Horner-Wittig reaction with carbonyl compounds is described. The E Z ratio of geometrical isomers of 1 was determined and briefly investigated. The X-ray diffraction structures of ( Z )-1-chloro-1-p-tolylsulfinyl-2-phenyl-ethene and (Z)-1-chloro-1-p-tolylsulfinyl-2-(2-thienyl)-ethene are reported.

CONFORMATION OF OXATHIAPHOSPHOLANE AND DITHIAPHOSPHOLANE RINGS IN THE SOLID STATE

In this paper, the geometry and conformation of oxathiaphospholane and dithiaphospholane rings in the solid state are described on the basis of our recent work and compared with literature data. For oxathiaphospholane rings in the solid state, both envelope and half-chair conformations, differently distorted, are observed. In oxathiaphospholane rings with the envelope conformation, the endocyclic carbon atom next to the ring oxygen atom is in the flap position. For dithiaphospholane compounds, the heterocyclic rings prefer a half-chair conformation or the conformation intermediate between half-chair and envelope forms; the envelope conformation is observed only in one case.

SOLID STATE CONFORMATION AND 31P CP/MAS NMR STUDIES OF (5,5-DIMETHYL-1,3-DITHIAN-2-YL)TRIPHENYL-PHOSPHONIUM CHLORIDE AND (5,5-DIMETHYL-1,3-DITHIAN-2-YL)TRIMETHYL-PHOSPHONIUM CHLORIDE

Abstract The crystal structures of the title compounds, 5,5-dimethyl-2-triphenylphosphonio-1,3-dithiane 1b and 5,5-dimethyl-2-trimethylphosphonio-1,3-dithiane 4b, have been determined by X-ray methods. Structure solution by direct methods and refinement by least-squares gave R = 0.044 and 0.046, respectively. The 1,3-dithiane ring in 1b adopts a chair conformation with the triphenylphosphonium group being axial while in 4b the trimethylphosphonium group is equatorial. Comparison of bond distances in 1b and 4b suggests that the ns-σ∗ C-P negative hyperconjugation may be responsible for the anomeric effect operating in the S—C—P+ system. The 31P CP/MAS NMR spectra of both title compounds were recorded and discussed.