C2-symmetric chiral disulfoxide ligands in rhodium-catalyzed 1,4-addition: from ligand synthesis to the enantioselection pathway.

A family of chiral C(2)-symmetric disulfoxide ligands possessing biaryl atropisomeric backbones has been synthesized by using the Andersen methodology. Complete characterization includes X-ray crystallographic studies of all ligands and some of their rhodium complexes. Their synthesis, optical purity, electronic properties, and catalytic behavior in the prototypical rhodium-catalyzed 1,4-addition of phenylboronic acid to 2-cyclohexen-1-one are presented through an in depth study of this ligand class.

Improving Grubbs' II type ruthenium catalysts by appropriately modifying the N-heterocyclic carbene ligand.

The introduction of N-heterocyclic carbene ligands that incorporate correctly substituted naphthyl side chains leads to increased activity and stability in second generation ruthenium metathesis catalysts.

Unprecedented selectivity via electronic substrate recognition in the 1,4-addition to cyclic olefins using a chiral disulfoxide rhodium catalyst.

From zero to hero? Sulfoxides are generally not considered useful ligand entities in asymmetric metal catalysis. However, a chiral disulfoxide as a chelating ligand in the rhodium-catalyzed 1,4-addition of aryl boronic acids to cyclic, alpha,beta-unsaturated ketones and esters gives impressive catalytic results, thus opening the door to future applications of this new chiral ligand class.

Matching the chirality of monodentate N-heterocyclic carbene ligands: a case study on well-defined palladium complexes for the asymmetric alpha-arylation of amides.

N-Heterocyclic carbene ligands derived from C(2)-symmetric diamines with naphthyl side chains are introduced as chiral monodentate ligands, and their palladium complexes (NHC)Pd(cin)Cl are prepared. These compounds exist as a mixture of diastereomers, and the palladium complexes can be successfully separated and their absolute stereochemistry assigned. When used in the asymmetric intramolecular alpha-arylation of amides, oxindoles with quaternary carbon centers can be obtained in high yield and selectivity when correctly matching the chirality of the NHC complexes.

Asymmetric synthesis of mono- and dinuclear bis(dipyrrinato) complexes.

The diastereoselective syntheses of Zn(II) bis(dipyrrinato) helicates is reported, involving ligands templated by the incorporation of homochiral binol within the linker joining the two dipyrrinato units. The most diastereoselective formation of dinuclear bis(dipyrrinato) helicates to date is reported. The formation of either mononuclear or dinuclear helicates can be tuned by varying the length of the linker between the dipyrrinato units and by varying the complexation procedure.