A novel C2-symmetric bisphosphane ligand with a chiral cyclopropane backbone: synthesis and application in the Rh(I)-catalyzed asymmetric 1,4-addition of arylboronic acids

Metathetic approach to new NORPHOS-related bisphosphanes: facile synthesis and application in asymmetric hydrogenation

A highly efficient synthesis of new chiral bisphosphanes derived from the renowned NORPHOS ligand is presented. The synthesis involves ring-opening metathesis of NORPHOS dioxide with an external olefin, followed by saturation of the new double bonds and adjustment of the oxidation level of phosphorus centers oxidation level. The synthesized bisphosphanes retain the configuration and enantiomeric purity of the starting NORPHOS. Their utility as ligands in asymmetric catalysis is exemplified using an open-NORPHOS ligand in some benchmark Rh-catalyzed hydrogenations of enamides where excellent chemical yields and enantiomeric purities of the products have been secured. The proposed protocol demonstrated the possibility of a straightforward synthesis of new chiral catalysts to be utilized in the asymmetric synthesis of pharmaceutically important compounds, such as amino acid derivatives.

Hierarchical Self-Assembly of a Water-Soluble Organoplatinum(II) Metallacycle into Well-Defined Nanostructures

A water-soluble metallosupramolecular hexagon containing pendant methyl viologen (MV) and trimethylammonium units at the vertices has been synthesized via an organoplatinum(II) ← pyridyl coordination-driven self-assembly reaction. The MV units of the metallacycle were further utilized in the formation of a heteroternary complex with cucurbit[8]uril and a galactose-functionalized naphthalene derivative, yielding a metallacycle-cored carbohydrate cluster that was subsequently ordered into nanospheres and tapes, depending upon the concentration.