Efficient Rh(I)-Catalyzed Direct Arylation And Alkenylation Of Arene C-H Bonds Via Decarbonylation Of Benzoic And Cinnamic Anhydride

Transition metal-catalyzed activation of aromatic C-H bonds followed by new C-C bond formation has been paid considerable attention in organic synthesis.In this thesis, efficient regioselective direct arylation and alkenylation of aromatic C-H bonds by Rh(â… ) catalysis using aromatic carboxylic and cinnamic anhydrides as the coupling partners via decarbonylative C-H bond activation of arene or N-heteroaromatic substrates was investigated under phosphine-free conditions.Rh(â… )-catalyzed direct arylation and alkenylation of aromatic C-H bonds using anhydrides as the coupling partners under phosphine-free conditions were successfully realized.Under the optimal conditions,the corresponding arylation and alkenylation compounds were formed in isolated yields up to 97%with excellent regio- / stereoselectivities.Three-component competition reactions were carried out to explore the reactivity of anhydrides and chlorides under the typical conditions.The results have revealed that the present catalytic system is much more efficient than the Rh(â… )/aroyl chloride system for the same purpose.A possible reaction mechanism is proposed.An anhydride is oxidatively added to the Rh(â… ) species to form an aroylcarboxylate metal complex[RCORh(â…¢)Cl(OCOR)] which undergoes decarbonylation to form Rh(â…¢)-arylcarboxylate intermediate.This intermediate reacts with arene to generate a C-H bond activation complex via intramolecular ortho-chelating assistance in the presence of Na₂CO₃ base.The desired product is then produced via the reductive elimination of C-H bond activation complex.All the target compounds were characterized by ¹H NMR,¹³C{¹H} NMR,and HRMS analyses.