Transition-Metal-Catalyzed C-H Bond Activation for the Formation of C-C Bonds in Complex Molecules.

Site-predictable and chemoselective C-H bond functionalization reactions offer synthetically powerful strategies for the step-economic diversification of both feedstock and fine chemicals. Many transition-metal-catalyzed methods have emerged for the selective activation and functionalization of C-H bonds. However, challenges of regio- and chemoselectivity have emerged with application to highly complex molecules bearing significant functional group density and diversity.

Ruthenium-Catalyzed Monoselective C-H Methylation and -Methylation of Arenes.

Site-selective installation of C-Me bonds remains a powerful and sought-after tool to alter the chemical and pharmacological properties of a molecule. Direct C-H functionalization provides an attractive means of achieving this transformation. Such protocols, however, typically utilize harsh conditions and hazardous methylating agents with poor applicability toward late-stage functionalization.

Catalysis with cycloruthenated complexes.

Cycloruthenated complexes have been studied extensively over the last few decades. Many accounts of their synthesis, characterisation, and catalytic activity in a wide variety of transformations have been reported to date. Compared with their non-cyclometallated analogues, cycloruthenated complexes may display enhanced catalytic activities in known transformations or possess entirely new reactivity.

Luminescent Bis(bipyridyl)ruthenium(II) Complexes with 1,2-Azolylamidino Ligands: Photophysical, Electrochemical Studies, and Photocatalytic Oxidation of Thioethers.

New 1,2-azolylamidino complexes -[Ru(bipy)(NH═C(R)az*-κ,)](OTf) (R = Me, Ph; az* = pz, indz, dmpz) are synthesized via chloride abstraction after a subsequent base-catalyzed coupling of a nitrile with the previously coordinated 1,2-azole. The synthetic procedure allows the easy obtainment of complexes having different electronic and steric 1,2-azoylamidino ligands. All of the compounds have been characterized by H, C, and N NMR and IR spectroscopy and by monocrystal X-ray diffraction.

Asymmetric [2+2] photocycloaddition via charge transfer complex for the synthesis of tricyclic chiral ethers.

The asymmetric synthesis of chiral polycyclic ethers by an intramolecular [2+2] photocycloaddition is described. This process proceeded through a photocatalytically active iminium ion-based charge transfer (CT) complex under visible light irradiation. In this way a stereocontrolled [2+2] photocycloaddition is enabled leading to tricyclic products with good enantiomeric ratios.

Photocatalytic Water-Soluble Cationic Platinum(II) Complexes Bearing Quinolinate and Phosphine Ligands.

Cationic Pt(II) complexes ([Pt(QO/S)(P∧P)]X), having 8-oxy or 8-thioquinolinate (QO/S) and seven different mono- or bidentate phosphines as ligands, have been synthesized and characterized. The photophysical, stability, and photocatalytic properties of those complexes were studied and compared to that of the parent [Pt(QO/S)(dmso)(Cl)]. The coordination of phosphines induced a red-shift in the absorption energy of the MLCT band, whereas the emission wavelength of the complexes only depended on the nature of the quinolinate ligand.

Visible light photocatalytic asymmetric synthesis of pyrrolo[1,2-a]indoles via intermolecular [3+2] cycloaddition.

The intermolecular diastereoselective and enantioselective synthesis of pyrrolo[1,2-a]indoles is developed through a [3+2] cycloaddition between silyl-indole derivatives and α,β-unsaturated N-acyl oxazolidinones by merging photocatalysis and Lewis acid catalysis.