Oxidative NHC-Catalyzed [3 + 2] Annulation Of Enals With ?-amino Esters For The Effective Synthesis Of Pyrrolidinones With A Quaternary Carbon Center

In recent years,N-heterocyclic carbene(NHC)catalysis have emerged as a powerful tool in organic synthetic transformations.As the reaction of N-heterocyclic carbene catalysis has its own unique catalytic model,and simple operation,low toxicity and low byproducts,in line with the requirements of modern green chemistry,so that it gradually developed into a relatively independent and complete system.In addition,The NHC-catalyzed generation of ?,?-unsaturated acyl azoliums from various carbonyl compounds has been well established and found broad application in organic synthesis.Functionalized 2-pyrrolidinones or y-butyrolactams containing a quaternary carbon center are important structural subunits frequently encountered in compounds displaying broad and significant biological and pharmacological activities.This paper reports an organocatalytic efficient synthetic approach to pyrrolidinones containing a quaternary carbon center.The reaction between enals and protected a-aminomalonates is catalyzed by N-heterocyclic carbene catalysts to afford the potential pharmaceutical and clinical significant lactams in moderate to excellent yields under oxidative conditions.Preliminary investigation of an enantioselective variant of this methodology exhibited high substrate tolerance and good application prospects.This article consists of the following three parts:1.Research history,structures and classification,typical catalytic reactions and mechanisms of N-heterocyclic carbene(NHC)catalysis were described in this part in detail.2.Commonly used achiral and chiral catalysts of N-heterocyclic carbene(NHC)have been synthesized.All target molecules were investigated by Nuclear Magnetic Resonance Spectroscopy and Carbon Spectroscopy,In addition,We tested their activity by reported reaction.3.Broad and significant biological and pharmacological activities of pyrrolidinones,as well as the synthesis status quo of such compounds were described in this part in detail.The reaction that oxidative NHC-Catalyzed[3+2]annulation of Enals with a-Amino Esters for the effective synthesis of pyrrolidinones with a quaternary carbon center has been developed in this part.We found the optimization of the Reaction Conditions by screening catalysts,oxidizing agents,bases,solvents,temperatures etc.Then the generality of the reaction was investigated.Finally,Preliminary enantioselective study of this methodology was investigated.