Iron-Mediated Carboarylation/Cyclization of Propargylanilines with Acetals: A Concise Route to Indeno[2,1‑<i>c</i>]quinolines

FeCl₃- and FeBr₃-mediated tandem carboarylation/cyclization of propargylanilines with diethyl benzaldehyde acetals furnished the tetracyclic core of indeno­[2,1-<i>c</i>]­quinolines. 5-Tosyl-6,7-dihydro-5<i>H</i>-indeno­[2,1-<i>c</i>]­quinoline and 7<i>H</i>-indeno­[2,1-<i>c</i>]­quinoline derivatives were obtained in good to excellent yields, respectively, by tuning the FeX₃ loadings and/or reaction temperatures

Dimeric Ruthenium(II)-NNN Complex Catalysts Bearing a Pyrazolyl-Pyridylamino-Pyridine Ligand for Transfer Hydrogenation of Ketones and Acceptorless Dehydrogenation of Alcohols

Dimeric pincer-type ruthenium­(II)-NNN complexes bearing an unsymmetrical pyrazolyl-pyridylamino-pyridine ligand were prepared and characterized by NMR, elemental analysis, and X-ray single crystal structural determination. These complexes exhibited very high catalytic activity for both transfer hydrogenation of ketones and acceptorless dehydrogenation of secondary alcohols, achieving TOF values up to 1.9 × 10⁶ h^–1 in the transfer hydrogenation of ketones. The high catalytic activity of the Ru­(II) complex catalysts is attributed to the presence of the unprotected NH functionality in the ligand and hemilabile unsymmetrical coordination environment around the central metal atoms in the complex

NHTs Effect on the Enantioselectivity of Ru(II) Complex Catalysts Bearing a Chiral Bis(NHTs)-Substituted Imidazolyl-Oxazolinyl-Pyridine Ligand for Asymmetric Transfer Hydrogenation of Ketones

Pincer-type ruthenium­(II)-NNN complex catalysts bearing a chiral bis­(NHTs)-substituted imidazolyl-oxazolinyl-pyridine ligand were synthesized and structurally characterized by NMR, IR, elemental analysis, and X-ray single-crystal crystallographic determinations. The two NHTs groups substituted on the imidazolyl moiety of the chiral NNN ligand exhibited a remarkable effect on the enantioselectivity of the Ru­(II)-NNN complexes for the asymmetric transfer hydrogenation (ATH) of ketones. The Ru­(II)-NNN complex bearing a chiral (NHTs)₂-substituted imidazolyl-(isopropyl)­oxazolinyl-pyridine ligand exhibited excellent catalytic activity, reaching an enantioselectivity up to 99.9% ee for the target alcohol products

Acceptorless Dehydrogenation of <i>N</i>‑Heterocycles and Secondary Alcohols by Ru(II)-NNC Complexes Bearing a Pyrazoyl-indolyl-pyridine Ligand

Ruthenium­(II) hydride complexes bearing a pyrazolyl-(2-indol-1-yl)-pyridine ligand were synthesized and structurally characterized by NMR analysis and X-ray single crystal crystallographic determinations. These complexes efficiently catalyzed acceptorless dehydrogenation of <i>N</i>-heterocycles and secondary alcohols, respectively, exhibiting highly catalytic activity with a broad substrate scope. The present work has established a strategy to construct highly active transition metal complex catalysts and provides an atom-economical and environmentally benign protocol for the synthesis of aromatic <i>N</i>-heterocyclic compounds and ketones

NHTs Effect on the Enantioselectivity of Ru(II) Complex Catalysts Bearing a Chiral Bis(NHTs)-Substituted Imidazolyl-Oxazolinyl-Pyridine Ligand for Asymmetric Transfer Hydrogenation of Ketones

Pincer-type ruthenium­(II)-NNN complex catalysts bearing a chiral bis­(NHTs)-substituted imidazolyl-oxazolinyl-pyridine ligand were synthesized and structurally characterized by NMR, IR, elemental analysis, and X-ray single-crystal crystallographic determinations. The two NHTs groups substituted on the imidazolyl moiety of the chiral NNN ligand exhibited a remarkable effect on the enantioselectivity of the Ru­(II)-NNN complexes for the asymmetric transfer hydrogenation (ATH) of ketones. The Ru­(II)-NNN complex bearing a chiral (NHTs)₂-substituted imidazolyl-(isopropyl)­oxazolinyl-pyridine ligand exhibited excellent catalytic activity, reaching an enantioselectivity up to 99.9% ee for the target alcohol products

A Highly Active Ruthenium(II) Pyrazolyl–Pyridyl–Pyrazole Complex Catalyst for Transfer Hydrogenation of Ketones

Ruthenium­(II) complexes bearing a pyrazolyl–pyridyl–pyrazole ligand were synthesized and exhibited exceptionally high catalytic activity in the transfer hydrogenation of ketones in refluxing isopropyl alcohol, reaching final TOFs up to 720 000 h^–1. The β-NH functionality of the pyrazole arm in the ligand demonstrated a remarkable acceleration effect on the reaction rate. The unsymmetrical nature (hemilability) and presence of the convertible NH group of the ligand is attributed to the high catalytic activity of the complex catalyst

Iron-Mediated Carboarylation/Cyclization of Propargylanilines with Acetals: A Concise Route to Indeno[2,1‑<i>c</i>]quinolines

FeCl₃- and FeBr₃-mediated tandem carboarylation/cyclization of propargylanilines with diethyl benzaldehyde acetals furnished the tetracyclic core of indeno­[2,1-<i>c</i>]­quinolines. 5-Tosyl-6,7-dihydro-5<i>H</i>-indeno­[2,1-<i>c</i>]­quinoline and 7<i>H</i>-indeno­[2,1-<i>c</i>]­quinoline derivatives were obtained in good to excellent yields, respectively, by tuning the FeX₃ loadings and/or reaction temperatures

FeCl₃·6H₂O‑Catalyzed Alkenylation of Indoles with Aldehydes

FeCl₃·6H₂O-catalyzed efficient C3-alkenylation of indoles was realized through the condensation of aldehydes and indole derivatives in the presence of 2 equiv of ethanol at ambient temperature, forming 3-vinylindoles in up to 93% yields. Ethanol promoted formation of the desired products. An obvious solvent effect was observed, and bisindoles were identified as the reaction intermediates

Photoredox-Catalyzed C–H Arylation of Internal Alkenes to Tetrasubstituted Alkenes: Synthesis of Tamoxifen

Visible-light-induced direct C–H arylation of <i>S,S</i>-functionalized internal alkenes, that is, α-oxo ketene dithioacetals and analogues, has been efficiently realized with aryldiazonium salts (ArN₂BF₄) as coupling partners and Ru­(bpy)₃Cl₂·6H₂O as photosensitizer at ambient temperature. The strategy to activate the internal olefinic C–H bond by both the alkylthio and electron-withdrawing functional groups was investigated. The synthetic protocol was successfully applied to the synthesis of all-carbon tetrasubstituted alkenes including tamoxifen

Photoredox-Catalyzed C–H Arylation of Internal Alkenes to Tetrasubstituted Alkenes: Synthesis of Tamoxifen

Visible-light-induced direct C–H arylation of <i>S,S</i>-functionalized internal alkenes, that is, α-oxo ketene dithioacetals and analogues, has been efficiently realized with aryldiazonium salts (ArN₂BF₄) as coupling partners and Ru­(bpy)₃Cl₂·6H₂O as photosensitizer at ambient temperature. The strategy to activate the internal olefinic C–H bond by both the alkylthio and electron-withdrawing functional groups was investigated. The synthetic protocol was successfully applied to the synthesis of all-carbon tetrasubstituted alkenes including tamoxifen