Enolate SAr of unactivated arenes [(η-arene)RuCp] intermediates.

A series of complexes of the general formula [(η-arene)RuCp][PF] (where arene = aryl halides or nitroarenes) were synthesised and the arene ring was found to be reactive towards an intermolecular nucleophilic aromatic substitution (SAr) reaction with a series of cyclic 1,3-diones. Competition experiments indicated that leaving group ability of the aryl halides and nitroarenes went in the order of F ≫ NO > Cl > Br. Following SAr, the arene rings were liberated quantitatively a rapid photolysis reaction (<15 min).

As Nice as π: Aromatic Reactions Activated by π-Coordination to Transition Metals.

π-Coordination of aromatic molecules to metals dramatically alters their reactivity. For example, coordinated carbons become more electrophilic and C-H bonds of coordinated rings become more acidic. For many years, this change in reactivity has been used to trigger reactions that would not take place for uncoordinated arenes, however, there has been a recent resurgence in use of this technique, in part due to the development of catalytic reactions in which π-coordination is transient.

Ruthenium catalyzed remote C4-selective C-H functionalisation of carbazoles via σ-activation.

We report the C4-selective C-H alkylation of carbazole derivatives furnished with a pyrimidine directing group at N9. This was realized using ruthenium catalyzed σ-activation methodology, whereby C-H activation at C1 enables the interaction of this ruthenacycle, at the para position to the metal center, with tertiary alkyl radicals.

Ruthenium-Catalyzed para-Selective C-H Alkylation of Aniline Derivatives.

The para-selective C-H alkylation of aniline derivatives furnished with a pyrimidine auxiliary is herein reported. This reaction is proposed to take place via an N-H-activated cyclometalate formed in situ. Experimental and DFT mechanistic studies elucidate a dual role of the ruthenium catalyst.

Use of the Hydantoin Directing Group in Ruthenium(II)-Catalyzed C-H Functionalization.

Ruthenium(II)-catalyzed C-H functionalization of N-arylhydantoins is herein described. The biologically relevant hydantoin (imidazolidinedione) heterocycle functions as a weakly coordinating directing group in a C-H alkenylation reaction. The reaction gave a wide scope of 23 examples with yields up to 94% in the green solvent 2-MeTHF.

Constrained beta-proline analogues in organocatalytic aldol reactions: the influence of acid geometry.

7-Azabicyclo[2.2.1]heptane-2-carboxylic acid 11 was prepared in enantiopure form, and its catalytic potential in the direct aldol reaction between acetone and 4-nitrobenzaldehyde was assessed.

Aza-Prins-pinacol approach to 7-azabicyclo[2.2.1]heptanes: syntheses of (+/-)-epibatidine and (+/-)-epiboxidine.

The syntheses of (+/-)-epibatidine and (+/-)-epiboxidine have been accomplished from commercial 2-methoxy-3,4-dihydro-2H-pyran. A recently developed aza-Prins-pinacol rearrangement was employed for the construction of the key 7-azabicyclo[2.2.