Study On C-N Bond Cleavage Reaction Of N-Alkoxyamides Based On Arynes

Aryne compounds with high reactivity have always attracted attention in the field of synthesis,especially after the development of kobayashi aryne precursors in 1983,they have been widely used in various transition metal catalysis,nucleophilic addition,cyclization and σ-bonds insertion into the reaction.Due to its special push-pull electronic structure,N-alkoxyamides have stronger nucleophilicity of nitrogen atoms,and they can be used as reaction substrates to prepare various compounds under the conditions of transition metal catalysis and metal free participation.Based on this,the first chapter of this thiesis discusses the research progress of aryne and their involved reactions,as well as the reaction types of N-alkoxyamides.According to previous reports,N-alkoxyamides are mainly used as substrates for the synthesis of amides and esters,and there are almost no reports on the synthesis of cyclic ketones.It can be seen from the amide structure that the cleavage process of the C(O)-N bond is required to obtain ketone compounds.Therefore,we hope to develop novel organic synthesis methodologies by inserting arynes into N-alkoxyamides to cleave the amide bonds.The research contents of this thesis mainly include:In Chapter 2,we developed a Pd(II)-catalyzed C-H bond activation/C-N bond cleavage cyclization reaction of N-alkoxyamides with arynes,and successfully synthesized9,10-dihydrophenanthrenone derivatives.The functional group of the reaction has a wide tolerance range and high yield,and the reaction mechanism of the eight-membered palladium ring intermediate is proposed for the first time,and it is further proved that the bivalent copper salt promotes the occurrence of the cyclization reaction through the oxidative cleavage of methoxyamine.In Chapter 3,we realized a novel amide decarboxylation modification method under mild conditions without the addition of light or metal catalysts.In this reaction,the sequential nucleophilic addition reaction of aryne with N-alkoxyamides promotes C(O)-N bond cleavage,decarboxylation cyclization,and the formation of novel acridine fluorescent materials.It can provide real-time monitoring of decarboxylation reaction through analytical techniques such as mass spectrum.This reaction is also applicable to the decarboxylation of amino acids,which is expected to realize the diversified modification of peptides in the later research.