Study On Ruthenium-Catalyzed Demanding Olefin Metathesis:Constructing 2(5H)-Furanones By Hydrogen-Bonding-promoted RCM And Synthesis Of N-(4-indolyl)-N-Hetercyclic Carbenes

Ruthenium catalyzed olefin metathesis reaction is one of the most commonly used synthesis methods,but there is still no effective method for the demanding olefin metathesis reaction.In order to solve the problem of low substrate reactivity and poor catalyst stability in such reactions,we envisage achieving activation and stabilization of the catalyst in different ways.Based on this idea,this thesis studied the hydrogen bond-activated olefin ring-closing metathesis(RCM)reaction and the synthesis of N-(4-indolyl)-nitrogen heterocyclic carbene(NHC).The main research work of this thesis includes:1.Construction of a double bond multi-substituted 2(5H)-furanone by hydrogen bond-promoted RCM reaction.2(5H)-furanone is a structural fragment commonly found in natural products and active drug molecules.The construction of double-bonded and multi-substituted 2(5H)-furanone has important application value.In the early stage of this group,we have established a strategy for constructing 5,6-dihydro-?-pyrone by hydrogenation of the substrate 2-hydroxymethylacryloyl group and the catalyst.To construct 2(5H)-furanone,this paper also uses this strategy..The results confirmed that the allylic hydroxyl group of the substrate promoted the reaction,established a polyamine removal treatment method,and explored the influence of substrate structure change on the reactivity.This study shows that the hydrogen bonding-promoted RCM reaction has a good application prospect in the double bond multi-substituted 2(5H)-furanone.2.Design and synthesis of N-(4-indolyl)NHC.The Hoveyda-Grubbs second generation type ruthenium carbene catalyst is often used for large sterically hindered RCMs,but there is a problem of insufficient stability.We propose to replace the N-aryl group of the NHC ligand with a larger aryl group such as a fluorenyl group in order to improve the stability of the ruthenium catalyst while increasing the possibility of activating the catalyst by non-covalent interaction.In this thesis,the design and synthesis of dihydroimidazole-type N-(4-indolyl)NHC ligands were studied.The synthesis route of indol intermediates was established and optimized,and various 4-amino indol and grasses amide indol intermediate were obtained.Moreover,a synthetic method of the target compound is basically established.This study laid the foundation for further study of the coordination properties and catalytic applications of N-(4-indolyl)NHC.