Synthesis Of Polyenic 1,4-diones Directly From α,β-unsaturated Methyl Ketones And Studies On The Mechanism Of The Self-sorting Tandem Reaction

Environmentally friendly,simple,highly efficient and atomic-economic method is the new trend of synthetic organic chemistry.Considering of atomic-economy,highly efficiency and green chemistry,tandem reaction and multicomponent reaction strategies have been rapidly developed in recent years.Sometimes,complicated compounds can be obtained via multi-step reaction in one-pot through these synthetic strategies.Self-sorting behavior of molecular cluster the ability to efficiently distinguish between self and nonself is a common property in complicated system.A novel synthetic reaction strategy-self-sorting tandem reaction which is a parallel tandem reaction pattern based on molecular self-sorting property-is presented in this thesis.Simultaneously,an efficient way to synthesize polyenic 1,4-diones fromα,β-unsaturated methyl ketones is developed. In addition,a new method for selective iodination at the a'-position ofα,β-unsaturated ketones is found during the investigation of the self-sorting tandem reaction mechanism. Additionally,the mechanism of Hantzsch reaction is also studied during the synthesis of 1,4-dihydroxypyridine compounds,which further verified our hypothesis of the self-sorti self-sorting tandem reaction mechanism.The main content is as follows:In chapter 1,1,4-dione compounds are important intermediates in organic synthesis, and can be used to synthesize of five-numbered heterocycles(furan,thiophene,and pyrrole),which consisit the main framework of some natural products.Some of them also present good biological activity.So we summarized the synthetic methods of 1,4-dione compounds,and put forward the research idea of this theis based on the concept of self-sorting.In chapter 2,based on the self-sorting behavior of molecular cluster,we proposed the self-sorting tandem reaction which was different from classical tandem reaction and multicomponent reaction.Twelve a,P-unsaturated methyl ketonesⅡ-2 were synthesized via classical aldol condensation reaction,polenic 1,4-dionesⅡ-3 were obtained via coupling of two sp~3 C-H bonds of methyl groups in the presence of copper(Ⅱ) oxide, iodine and dimethyl sulfoxide.Compound(E)-Ⅱ-3j was further confirmed by X-ray single crystal diffraction.In chapter 3,an efficient approach toα.β-unsaturatedα'-iodo ketones fromα,β-unsaturated ketones by selective iodination at theα'-positon without effect on the double bond and aromatic ring in the presence of copper(Ⅱ) oxide/iodine is described.This is the first systematical investigation of the synthesis of important intermediatesα,β-unsaturatedα'-iodo ketones directly fromα,β-unsaturated ketones. In chapter 4,nine 1,4-dihydropyridine compoundsⅣ-2 were synthesized according to Hantzsch Reaction.The reaction mechanism was also studied,and it was found that when compoundsⅣ-1a/Ⅳ-1c,Ⅳ-1a/Ⅳ-1d,Ⅳ-1b/Ⅳ-1c,Ⅳ-1b/Ⅳ-1d were mixed with m-Nitrobenzaldehyde and ammonium acetate,asymmetric 1,4-dihydro-pyridine compounds were obtained with little symmetric ones.Therefore,the self-sorting tandem mechanism was further verified through the synthesis of 1,4-dihydropyridine compounds via Hantzsch Reaction.