Palladium-catalyzed Meta-C-H Alkylation And Ortho Nitration Of Phenylalanine Methyl Ester Derivatives

Phenylalanine derivatives have good biological activity and medicinal value,which are widely used in medicine,pesticides,fine chemical products.At the same time,these compounds are also very important intermediates in organic synthesis.Therefore,the synthesis of these compounds has always been a research focus for organic synthesis workers.This paper contains three parts:The first chapter introduces the development of the Catellani reaction including ortho-alkylation,ortho-arylation,ortho-amination,ortho-acylation,the meta-C-H bond activation of aryl rings bearing a chelating directing group by Pd?II?/Pd?IV?/norbornene catalysis.Furthermore,We summarize the development of the nitration via transition metal-catalyzed C-H bond activation in recent years.The second chapter of this thesis describes the meta-alkylation of the nosyl-protected phenylalanine methyl esters with a variety of alkyl iodides at 80 ^oC catalyzed by palladium/norbornene in combination with pyridine ligands,using AgOAc as oxidant and TBME as solvent.In most cases,it allows for the preparation of the desired products in moderate to good yields and tolerates a wide range of substrates.The third chapter of this thesis describes the palladium-catalyzed reaction of picolinamide?PA?-protected phenylalanine methyl esters under mild conditions.It offers a good way for highly selective nitration of aromatic C-H bond in the presence of K₂S₂O₈.This protocol shows moderate functional group tolerance and medium reactivity.