Site-Specific Phenylation of Pyridine Catalyzed by Phosphido-Bridged Ruthenium Dimer Complexes:  A Prototype for C−H Arylation of Electron-Deficient Heteroarenes

Abstract

Direct and selective catalytic arylation of alpha-C-H bond in pyridine with iodobenzene was achieved in up to 70% yield. Phosphido-bridged bisruthenium complexes 6a and 6b arising from Ru3(CO)12 and PPh3 were identified as active catalysts. The formation of complexes 6a and 6b was investigated, a sequence of C-H and C-P bond cleavage, cluster fragmentation, and disproportionation was established, and the intermediate ruthenium complexes lying on this pathway were isolated and fully characterized.

Catalytic C–C coupling through C–H arylation of arenes or heteroarenes

“…As shown in Fig. 1 these species activate pyridine through bridging the two Ru atoms, but unfortunately are not active as catalysts [103].…”

Transition metals in organic synthesis: Highlights for the year 2005

“…Palladium catalyzed a related reaction [381]. (21) Ruthenium catalyzed couplings in the 2-position of pyridine with iodobenzene [382], of N-unprotected indoles and pyrrole using aryliodides [383] and of N-phenylpyrrolidine [384].…”

“…Zirconacyclopentenes react with acyl cyanides to give either 1-ene-5-ones or cyclopentadienes depending on the reaction temperature (Eqs. (382) and (383)) [1565]. Titanacyclopentenes were coupled with nitriles to form 3-cyclopentenylamines (Eq.…”

Synthesis of Pyridines by Carbenoid‐Mediated Ring Opening of 2H‐Azirines

“…[3] More recently, synthesis of pyridines based on cycloaddition and transition-metal catalysis has been reported. [5] Despite these progress, a flexible synthesis of pyridines allowing access to diverse substitution patterns continues to draw a great deal of interest from the synthetic community. [5] Despite these progress, a flexible synthesis of pyridines allowing access to diverse substitution patterns continues to draw a great deal of interest from the synthetic community.…”