Study On The Synthesis Of Oxygenbridged Dinitrogen Heterocyclic Compounds And Asymmetric Halogenation Of Olefins Under Organic Catalysis

Due to the simple reaction operation,high stability,environmental friendliness,extensive functional group tolerance,and structural diversity of organic molecules,organic catalysts are widely used as valuable tools for developing new chemical reactions.At the same time,with the development of asymmetric catalysis,or ganic catalytic asymmetric synthesis has become a research hotspot that has received widespread attention.Heteroatoms and heterocyclic skeletons are the core skeletons of many biologically active molecules,such as diazepines,benzo1,3-oxazines,and so on.Previously,various ways to synthesize such compounds have been reported,but few methods have been reported for the effective synthesis of 1,5-diazepines.Moreover,currently,strategies developed mostly use metal catalysis,and most strategies have poor substrate applicability and relatively harsh reaction conditions.Chiral halogenated compounds,as a valuable class of compounds,are commonly used as multifunctional synthetic intermediates.Many methods for the synthesis of chiral halogenated compounds through asymmetric halogenation functionalization of olefins have been developed in the past decade.However,these strategies have certain limitations in terms of yield and stereoselectivity.In order to explore ways to quickly and efficiently construct the above two types of molecular skeletons,the following research contents and schemes have been designed based on the mode of organic catalysis:(1)In this paper,starting from 1-alkynyl-2-naphthylamine derivatives and reacting with o-aminobenzaldehyde derivatives under the catalysis of small organic molecules,a multi epoxybridged diazooctane compound was synthesized.Using phosphoric acid(10% mol)as a catalyst,this reaction can obtain corresponding oxo bridged diazo heterocyclic compounds with good yields(>70%),excellent diastereoselectivity(>20:1 dr),and wide substrate applicability.The reaction conditions are mild,requiring only 4 hours of reaction at room temperature.This new method has high atomic utilization and can be successfully scaled up to gram scale(68%yield).(2)This article designs to introduce the double hydrogen bond donor group urea group into the ortho position of styrene,solve the regioselectivity problem of asymmetric halogenation functionalization of olefins through the guidance of urea groups,and control the stereoselectivity of the reaction under the catalysis of small organic molecules,thereby achieving high enantioselective halogenation functionalization of olefins.This work uses o-urea styrene derivatives as raw materials,N-bromosuccinimide(NBS)as an electrophilic bromine source,and trifluoroethanol as both a solvent and a nucleophilic reagent.Under the catalysis of cinchona base catalysts,corresponding o-brominated alkoxy compounds can be obtained with high yields(>80%)and excellent stereoselectivity(>90%).This method has good substrate applicability,while maintaining a high yield(72%)and excellent stereoselectivity(98%ee)to scale up the reaction to gram scale.The o-bromo substituted alkoxy compounds generated by the reaction can be converted into N-amide substituted indolines and indole derivatives through a series of derivatization experiments.