Photoactivated Transition-Metal Triggers for Ambient Temperature Enediyne and Dienyne Cyclization: Ruthenium-η6-Naphthalene Complexes

Synthesis and Coordination Chemistry of Fluorinated Cyclopentadienyl Ligands

The incorporation of fluorinated substituents in cyclopentadienyl anions leads to distinct changes in the properties of the corresponding metal complexes, e.g., with regards to electrochemical properties or metal–ligand bonding energies. This review summarizes the synthetic challenges of the preparation and coordination of fluorinated cyclopentadienyl anions.

1 Introduction

2 Fluorinated Cyclopentadienyls

3 Cyclopentadienyls with One CF3 Group

4 Cyclopentadienyls with Four CF3 Groups

5 Cyclopentadienyls with Five CF3 Groups

6 Cyclopentadienyls with ‘Fluorous Ponytails’

7 Cyclopentadienyls with C6F5 Groups

8 Trends in Interaction Energies

9 Conclusion

Transition-Metal Catalysis of Triene 6π Electrocyclization: The π-Complexation Strategy Realized

Triene 6π electrocyclization, wherein a conjugated triene undergoes a concerted stereospecific cycloisomerization to a cyclohexadiene, is a reaction of great historical and practical significance. In order to circumvent limitations imposed by the normally harsh reaction conditions, chemists have long sought to develop catalytic variants based upon the activating power of metal-alkene coordination. Herein, we demonstrate the first successful implementation of such a strategy by utilizing [(C₅ H₅ )Ru(NCMe)₃ ]PF₆ as a precatalyst for the disrotatory 6π electrocyclization of highly substituted trienes that are resistant to thermal cyclization. Mechanistic and computational studies implicate hexahapto transition-metal coordination as responsible for lowering the energetic barrier to ring closure. This work establishes a foundation for the development of new catalysts for stereoselective electrocyclizations.

Ortho C-H arylation of arenes at room temperature using visible light ruthenium C-H activation

A ruthenium-catalyzed ortho C–H arylation process is described using visible light. Using the readily available catalyst [RuCl₂(p-cymene)]₂, visible light irradiation was found to enable arylation of 2-aryl-pyridines at room temperature for a range of aryl bromides and iodides.

A ruthenium-catalyzed ortho C–H arylation process is described using visible light.