Study On 8-oxabicyclo [3.2.1] Octane Skeleton And Semipinacol Rearrangement Reaction

Multi-substituted THF units are widely present in biologically active natural products as well as drug molecules.The efficient construction of core units of the compounds with THF units has been an important subject in organic chemistry.Based on our previous work on α-C-H functionalization of ether and semipinacol rearrangement,this dissertation realized the construction of two types of multi-substituted THF units including 8-oxabicyclo[3.2.1]octane and spiro[benzofurancyclopentane] skeletons.The following four parts in this dissertation are mainly included:1.Background introduction of 8-oxabicyclo[3.2.1]octane skeletons.The progress in recent years of construction strategies for such skeletons was briefly described in this section.2.C-H oxidation/oxa-Cope rearrangement/Aldol reaction.We have successfully realized the functionalization of the carbon-hydrogen bond of allyl ether,benzyl ether and allylsulfonamide with the combination of oxa-Cope rearrangement and Aldol reaction,and efficiently constructed 8-oxa or azabicyclo[3.2.1]octane skeletons and multi-substituted THF structures.3.Background introduction of asymmetric semipinacol rearrangement reactions.This section briefly describes the development of asymmetric Semipinacol rearrangement reactions in recent years.4.Asymmetric one-pot [3+2] cyclization/semipinacol rearrangement reaction.Semipinacol rearrangement in our group was used to combine the different reactions in the tandem cyclization which realized the construction of complex structures with the multi-center and polycyclic system.The reaction was carried out from two easily available starting materials: allyl alcohol and substituted benzoquinone,The asymmetric construction of the spiro[benzofurancyclopentane] skeletons was realized by the classically used chiral copper(II)-bisoxazoline catalytic system with good to excellent enantioselectivities and diastereoselectivities and good yields.