Photoredox Catalysed Of Cyclopropyl Ring Opening Reaction And Electrochemical Synthesis Of Aziridine

It is well known visible-light and electricity are clean and green energy sources.Recently,visible-light photoredox catalysis and electrochemical emerged as highly efficient methods for organic syntheses,demonstrating advantages in a number of challenging reactions.The utilization of cyclopropyl group as radical clock was well-established for decades in mechanistic study to elucidate a radical pathway.Despite extensive examples of cyclopropyl group as radical probe,its corresponding synthetic application remained elusive.Aziridines are reactive nitrogen building blocks affording a variety of useful transformations.For example,aziridines serve as pharmaceuticals intermediates and as monomers for the fabrication of functional materials.We have developed a protocol for electrochemical syntheses of aziridines with a sulfamate as the nitrogen source.The protocol was compatible with triaryl-substituted alkenes and multisubstituted styrenes.This thesis incorporate:1.Difluoroalkylation/C-H Annulation Cascade Reaction Induced by Visible-Light Photoredox CatalysisWe developed a protocol for visible-light-induced photoredox difluoroalkylation/C-H annulation cascade reactions constructing substituted dihydronaphthalenes using a variety of alkylation reagents.2.E-Z Isomerization of 1,5-Bromotrichloromethylation Reaction Products and Trisubstituted Styrenes1,5-Bromotrichloromethylation of a-cyclopropylstyrenes via a radical chain pathway was achieved with Ir photocatalyst as a photoinitiator under visible-light irradiation.Z products were generated in nearly quantitative yields via a radical chain/energy-transfer pathway.This method could also be used for E-Z isomerization of trisubstituted styrenes with Z/E ratio up to 99:1 in excellent yields.3.Electrochemical Aziridination via Alkene Activation with a Sulfamate as Nitrogen SourceThe first direct aziridination of triaryl-substituted alkenes was achieved by means of an electrochemical process that could extend to multisubstituted styrenes.Specifically,hexafluoroisopropanol sulfamate was used as a nucleophilic nitrogen source,which added to the alkenes activated by anodic oxidation.Mechanistic experiments suggest that this electrochemical process proceeds via stepwise formation of two C-N bonds by means of reactions between cationic carbon species and the sulfamate.