Planar Chiral Rhodium Complex Based on the Tetrahydrofluorenyl Core for Enantioselective Catalysis.

A simple four-step route to a chiral tetrahydrofluorenyl rhodium catalyst from naturally occurring (-)-α-pinene was developed. Our approach does not use multistep and time-consuming procedures such as chiral HPLC or diastereomeric resolution. The key to success lies in the face-selective coordination of rhodium to the sterically hindered tetrahydrofluorenyl ligand, giving only one diastereomeric complex.

Tandem C-H Annulation Reaction of Benzaldehydes and Aminobenzoic Acids with Two Equivalents of Alkyne toward Isocoumarin-Conjugated Isoquinolinium Salts: A Family of Organic Luminophores.

A novel rhodium-catalyzed tandem C-H annulation of commercially available benzaldehydes and aminobenzoic acids with 2 equiv of alkyne is reported for the construction of isocoumarin-conjugated isoquinolinium salts that demonstrate diverse outstanding photoactivity. Depending on the substituents in the isoquinolinium moiety, they display either highly efficient fluorescence (up to 99% of quantum yield) or strong fluorescence quenching, which is provided by the transfer of the HOMO from the isoquinolinium to the isocoumarin moiety. Importantly, the functional groups in the benzaldehyde coupling partner also strongly affect the reaction selectivity, shifting the pathway to the formation of the photoinactive isocoumarin-substituted indenone imines and indenyl amines.

Triphenylcyclopentadienyl Rhodium Complexes in Catalytic C-H Annulations. Application for Synthesis of Natural Isocoumarins.

Efficient protocols for the synthesis of triphenylcyclopentadienyl rhodium halides [(1,2,4-CPhH)RhX] (,: X = Cl, I) starting from 1,2,4-triphenylcyclopentadiene or the cyclooctadiene derivative (1,2,4-CPhH)Rh(cod) () were developed. Iodide abstraction from with thallium or silver salts allowed us to prepare rhodocenium [(1,2,4-CPhH)RhCp]PF (PF) and mesitylene complex [(1,2,4-CPhH)Rh(mesitylene)](SbF) ((SbF)). Halides , (at 0.

Easy Access to Versatile Catalytic Systems for C-H Activation and Reductive Amination Based on Tetrahydrofluorenyl Rhodium(III) Complexes.

On the basis of the 1,2,3,4-tetrahydrofluorenyl ligand, a simple approach was developed to new effective rhodium catalysts for the construction of C-C and C-N bonds. The halide compounds [(η -tetrahydrofluorenyl)RhX ] (2 a: X=Br; 2 b: X=I) were synthesized by treatment of the bis(ethylene) derivative (η -tetrahydrofluorenyl)Rh(C H ) (1 a) with halogens. An analogous reaction of the cyclooctadiene complex (η -tetrahydrofluorenyl)Rh(cod) (1 b) with I is complicated by the side formation of [(cod)RhI] .

Effect of Cp-Ligand Methylation on Rhodium(III)-Catalyzed Annulations of Aromatic Carboxylic Acids with Alkynes: Synthesis of Isocoumarins and PAHs for Organic Light-Emitting Devices.

An efficient protocol was developed for the synthesis of π-extended isocoumarins and polycyclic aromatic hydrocarbons based on the oxidative coupling of aromatic carboxylic acids with internal alkynes catalyzed by (cyclopentadienyl)rhodium complexes. The coupling chemoselectivity strongly depends on whether Cp or the methylated Cp* ligands are used. The pentamethyl derivative [Cp*RhCl ] predominantly gives isocoumarins, while the non-methylated complex [CpRhI ] produces naphthalene derivatives.

The First Triple-Decker Complex with a Carbenium Center, [CpCo(μ-C B Me )RuC Me CH ] : Synthesis, Reactivity, X-Ray Structure, and Bonding.

The first derivative of the methylium cation with the triple-decker substituent, [CpCo(C B Me )RuC Me CH ]PF (2PF ), was synthesized from the reaction of the triple-decker complex CpCo(C B Me )RuCp* (1) with the salt of the trityl cation [CPh ] . The X-ray crystal structure of 2PF reveals that the methylium carbon is bound to the ruthenium with Ru-C bond length of 2.259 Å and corresponds to the description of its structure as η -fulvene-ruthenium.