Research On N-N Bond Activation Reaction Induced By Organic Hypervalent Iodine Salts

In recent years, organic hypervalent iodonium salts have been widely appliedand become the most active research field in modern organic synthesis chemistry dueto their characteristics of easy preparation, mild reaction condition, high selectivity andenvironmental friendly feature. In particularly, the diaryliodonium salts usually affordpowerful aryl group to react with a wide range of nucleophiles to synthsize valuablevarious aromatic compounds. Based on our group’s previous work about the researchof diaryliodonium salts, except for the arylation ability, we envision that the orthocarbon atom of the aryl group has certain nucleophilic ability to realize somecyclization and rearrangement reaction with high efficiency and high regioselectivity.In comparison to inactive pyridine, pyridine N-amidates show more nucleophilicability and has certain electrophilic ability as well. So induced by diaryliodonium salts,via the arylation of amidate nitrogen, the ortho carbon atom of the aryl group canattack the pyridine nitrogen ions and rearrange to the N-N bond centre to realize N-Nbond activation.In this thesis, pyridine N-amidates substrates induced by diaryliodoniumsalts catalyzed by10%Cu(OTf)2in DCE solvent could afford271-(N-aryl-4-methylphenylsulfonamido) pyridin-1-ium derivatives and211-(2-(4-methylphenylsulfonamido)aryl) pyridin-1-ium derivatives respectivelythrough controlling different reaction temperatures. This method features mild reactioncondition, high yields and simple operation.In this paper, the arylation compound was proved to be the intermediate ofthe final rearranged product through heating rearrangement experiment. This thesis focused on the study of the electronic effect of substituents on the aryl group andpyridine ring, which could influence the possibility and efficiency of the aryl grouprearrangement process. The structures of all separated target products werecharacterized by1H NMR,13C NMR, and HRMS and three different kinds ofmolecular structure were confirmed by X-Ray diffraction analysis. At last, theplausible mechanism was discussed and put forward.