Intramolecular Palladium-catalyzed Arylation Research Articles

Proton-Abstraction Mechanism in the Palladium-Catalyzed Intramolecular Arylation: Substituent Effects

The regioselectivity observed in the intramolecular palladium-catalyzed arylation of substituted bromobenzyldiarylmethanes as well as theoretical results demonstrate that the Pd-catalyzed arylation proceeds by a mechanism involving a proton abstraction by the carbonate, or a related basic ligand. The reaction is facilitated by electron-withdrawing substituents on the aromatic ring, which is inconsistent with an electrophilic aromatic-substitution mechanism. The more important directing effect is exerted by electron-withdrawing substituents ortho to the reacting site.

Synthesis of a triaza analogue of crushed-fullerene by intramolecular palladium-catalyzed arylation.

Alkylation and intramolecular palladium-catalyzed arylation allows for the ready synthesis of C57H33N3 from symmetrical triindole, a triaza analogue of truxene.

Imposing curvature on a polyarene by intramolecular palladium-catalyzed arylation reactions: A simple synthesis of Dibenzo

Palladium catalysis has been found to offer an effective solution-phase alternative to gas-phase flash vacuum pyrolysis as a method for converting the planar ring system of 7, 10-di(2-bromophenyl)fluoranthene (4) to that of the C(28)H(14) bowl-shaped fullerene fragment dibenzo[a,g]corannulene (5).

Synthesis of Spiro Polycyclic Aromatic Hydrocarbons by Intramolecular Palladium-Catalyzed Arylation

The palladium-catalyzed intramolecular arylation reaction has been applied to the synthesis of the spiro polycyclic aromatic hydrocarbons and planar polycyclic aromatic hydrocarbons by formation of a six-membered ring. The reaction proceeds more readily with aryl bromides substituted with electron-withdrawing groups by using palladium acetate in N,N-dimethylformamide as the solvent. For the less reactive p-methoxyaryl derivatives the use of LiI as an additive was shown to give the best results. The results obtained in the cyclization of nitro derivatives 21 and 23 suggest that the second step of the cyclization reaction is not an electrophilic substitution reaction.

New applications of organopalladium compounds in organic synthesis

Abstract