Studies On The Cleavage Functionalization Reaction Of Enaminones Carbon-Carbon Double Bond

Carbon-carbon double bond is one of the most foundamental and frequently available chemical bonds in nature,studies on the direction C-C double bond functionalization is an issue of strategic meaning.Enaminones are a series of important synthetic building blocks showing widespread application in the synthesis of various organic products.Because of the activation effect of the electron donating amino group and electron withdrawing carbonyl in the two ends,the enaminone double bond is evidently polarized,thus provide huge space in the research of the bond transformation.The work contents of this thesis are enaminone C-C double bond cleavage functionalization.By employing proper reaction partners to reaction with enaminone via different catalytic or reaction models,we have consequently achieved an array of new synthetic methods based on the enaminone C-C double bond cleavage.The reserch works consist of four sections.The first section,synthesis of?-ketothioamides with the reactions of enaminones and elemental sulfur.In the presence of 4-dimethylamino pyridine,the synthesis of?-ketothioamides is realized via sulfur functionalization based on the C-C double bond cleavage.The reactions require not any metal catalyst or additive to construct new C=S and C-N bonds via the tandem transfomormation of C=C and C-H bonds,thus affording a facile and practical method for the synthesis of N,N-disubstituted?-ketothioamides.The second section,microwave irradiated synthesis of?-diazoketones via the reactions of enaminones and methyl sulfonyl azide in pure water medium.Starting from enaminones and methyl sulfonyl azide,the synthesis of?-diazoketones is achieved in pure water with microwave irradiation.The method is advantageous in terms of sustainability as not any catalyst or additive is used in the reations.The target products are formed by means of the major[3+2]cycloaddition and subsequent decomposition.The third section,enaminone C=C double bond cleavage hydrolysis for the synthesis of?-hydroxyl ketones.The synthesis of?-hydroxyl ketones via enaminone C=C double bond cleavage-based hydroxylation is realized for the first time without using any catalyst or additive.The reaction process involves in the featured[3+2]cyclization and ring decomposition providing?-diazoketones as well as the subsequent?-diazoketone hydrolysis.Water acts as both medium and reactant during the reaction process,and the method is simple in operation and higly atom economical,possessing high application potential.The forth section,trifluoromethylatin by enaminone C=C double bond cleavage for the synthesis of?-trifluoromethyl ketones.By employing TBHP as oxidant,the new method for synthesizing?-trifluoromethyl ketones via the reactions of enaminones and CF₃SO₂Na is established.The reactions take place via free radical process to enable the construction of C-CF₃ bond.The reaction is good in application scope,and can be used in the late-stage elaboration of natural product.The labelling experiment using D₂O proves the water has participated the reaction by acting as hydroxyl donor.