Construction Of Axial And Helical Chirality Via Rh-Catalyzed Cleavage Of C-Si Bond And Synthesis Of Azoboronene Compounds

Chiral compounds exist widely in nature.They cannot coincide with their mirror images,so they exhibit different optical activities and may have completely different chemical properties which give important applications in the field of chemical medicine.In addition to the central chirality,chirality also includes axis chirality and helical chirality.Among them,the axial chirality is due to steric hindrance or electron effect that causes a single bond cannot rotate freely at a certain temperature,and multiple groups are arranged around the chiral axis,which is arranged in such a way that the molecules cannot coincide with their mirror images and express chirality.Helical chirality is caused by the fact that two isomers cannot overlap because they rotate in different directions.This thesis focuses on the efficient construction of axial chiral compounds containing silicon and spirene compounds containing silicon or boron with helical chirality,including the study of their optical properties.Chapter 1:Some strategies for the construction of chiral silanes and chiral spirosilanes catalyzed by transition metals are introduced,and a new strategy for the construction of chiral silicon-centric compounds is proposed using torsional tension of molecules to promote ring opening.Chapter 2:Using rhodium dicarbonyl chloride and phosphoramidite ligand based on TADDOL backbone as catalysts,the first rhodium-Narasaka acylation reaction catalyzed by rhodium was realized,and biaryl inhibitory rotation compounds containing ortho-major hindsilianol groups were synthesized with high enantioselectivity.The reaction has good substrate scope and the existence of torsional strain in the five-membered ring opening reaction is proved by calculation for the first time.Subsequently,we achieved the construction of a central chirality and an axial chirality by breaking a carbon-silicon bond by rhodium-catalyzed Narasaka acylation,and the newly synthesized phosphoramidite ligand and additive methanol played a key role in controlling enantioselectivity and enantioselectivity respectively in the ringopening reaction.Based on this work,we also realized that the kinetic separation of[7]spirosilane and[9]spirosilane provides an efficient method for the synthesis of silylcontaining helicene chiral compounds.Chapter 3:On the basis of the previous work of silosirospire,it was found that the introduction of heteroatoms can change the properties of heterosene and adjust the luminescence properties of molecules.We introduced nitrogen-boron heteroatoms by C-H bond boronation,efficiently synthesized nitroboron-heterosene and nitroboron heterosheiroene compounds,and studied the optical properties of the newly synthesized spirospermia and theoretical calculations.(1)N,B-heterocyclic fraction affects the optical properties of the helinene structure through conjugation effect,and its structure is further analyzed by X-ray crystallographic analysis.By comparing the[7]helicene and[9]henonene backbones of boron,it is found that the higher thick ring system obtains a higher asymmetric factor in circularly polarized luminescence.(2)Through the study of the optical properties of nitrogen-boron heterosiropelicene,the introduction of nitrogen-boron bonds can enhance the luminescence effect of molecules,and the fluorescence quantum yield can be as high as 84%.