Palladium-catalyzed Meta-selective C-H Alkenylation And Acetoxylation Of Arylacetic Acid

Arylacetic acid compounds are ubiquitous structural motifs found in many natural products,pharmaceuticals,and bioactive compounds.It is important to develop a method for synthesizing various functionalized arylacetic acid derivatives.At present,the direct meta-C-H functionalization of arylacetic acid compounds has proved to be more challenging.As far as we know,it is difficult to remove that the targeting group attached to the aryl acetate ring in the most of the literature so far.In order to overcome the limitations of existing methods,to achieve meta-functionalization of such compounds,it is significant to develop an easily introduced and removed targeting group.In this paper,Palladium-catalyzed remote meta-selective C-H functionalization of arylacetic acid has been developed using a pyrimidine template.This transformation is not only tolerated to a diverse range of arylacetic acid and alkene substrates,but also applicable to the synthesis of pharmaceutically active ibuprofen derivatives.Moreover,the pyrimidine template was readily removable and recyclable under mild conditions.Based on relevant literature,we reported a palladium(II)-catalyzed meta-C-H alkenylation and acetoxylation of arylacetic acid.Firstly,in order to explore the optimal reaction conditions,we screened solvent,amount of catalyst,type and amount of oxidant on this reaction.Subsequently,the scope and generality with repect to arylacetic acid and alkene substrates were examined under the optimal reaction conditions.Finally,a plausible mechanistic pathway was proposed based on the related reports.