New chiral zwitterionic phosphorus heterocycles: synthesis, structure, properties and application as chiral solvating agents.

A family of new chiral zwitterionic phosphorus-containing heterocycles (zPHC) have been derived from methylene-bridged bis(imidazolines). These structures were unambiguously determined, including single-crystal XRD analysis for two compounds. The stability, acid/base and electronic properties of these dipolar phosphorus heterocycles were subsequently investigated.

Levonantradol: asymmetric synthesis and structural analysis.

The first asymmetric synthesis of a synthetic cannabinoid levonantradol was accomplished, and the 3-D solution structure of its core architecture was confirmed by NMR and computational methods.

Preparation of dicationic palladium catalysts for asymmetric catalytic reactions.

The synthesis of Pd(OTf)(2)·2H(2)O is described. This was used to generate two different types of chiral dicationic palladium complexes for highly enantioselective addition of aromatic amines to α, β-unsaturated conjugate alkenes ([(R-BINAP)Pd(OH(2))(2)][OTf](2) and [(R-BINAP)Pd(μ-OH)](2)[OTf](2)). The resulting optically active N-arylated β-amino acid derivatives are valuable synthetic intermediates for the synthesis of biologically active molecules and peptidomimetics.

Determination of acid-base dissociation constants of very weak zwitterionic heterocyclic bases by capillary zone electrophoresis.

Thermodynamic acid-base dissociation (ionization) constants (pK(a)) of seven zwitterionic heterocyclic bases, first representatives of new heterocyclic family (2,3,5,7,8,9-hexahydro-1H-diimidazo[1,2-c:2',1'-f][1,3,2]diazaphosphinin-4-ium-5-olate 5-oxides), originally designed as chiral Lewis base catalysts for enantioselective reactions, were determined by capillary zone electrophoresis (CZE). The pK(a) values of the above very weak zwitterionic bases were determined from the dependence of their effective electrophoretic mobility on pH in strongly acidic background electrolytes (pH 0.85-2.