| Based on the urgent demand for environmentally benign chemical reactions and processes,direct C-H functionalization,which possesses various advantages such as step and atom economy,has made great progress and become a powerful tool for chemists to build complex molecular structures.In recent years,an atom-economic strategy called "[1,n]-hydride transfer/cyclization" has received widespread attention due to its ability to activate remote C(sp3)-H bonds to generate important heterocyclic compounds.However,the limited product structure that can be accessed and the requirement for precious catalysts restrict the application of this strategy.Therefore,the development of new reactions,especially the search for new hydride acceptors,use of inexpensive catalysts and construction of novel product structures,remains a great challenge.In response to this challenge,this dissertation innovatively developed the type of hydride acceptors through rational reaction design.Accordingly,a series of novel six-membered,seven-membered,and medium/larged-sized N-heterocycles were constructed via the[1,5]-hydride transfer/cyclization strategy.1)A new divergent synthesis reaction by the control of substrate and condition was developed.With the tandem[1,5]-hydride transfer/[1,7]-cyclization or[3+3]annulation of 2-indolyl aryl carbinols catalyzed by acid,a series of indoloazepine,indolodiazepine and polycyclic diindoles were synthesized.2)A new reaction of[1,5]-hydride transfer/[1,8]-cyclization catalyzed by acid was developed.Through substrate design,indole-annulated medium/large-sized N-heterocyclic compounds were synthesized from 4-indolyl aryl carbinols via tandem dehydroxylation/hydride transfer/cyclization,or followed protonation,ring expansion and deprotonation.3)A new 1,3-dipole-involved[1.5]-hydride transfer/[1,7]-cyclization reaction catalyzed by FeCl3 was developed.And a series of potentially bioactive 1,4-benzodiazepines were synthesized from aminomalonate hydrochloride and o-substituted aminobenzaldehyde via tandem condensation/[1,5]-hydride transfer/[1,7]-cyclization processes.4)A novel B F3·Et2O-catalyzed tandem condensation/[1,5]-hydride transfer/[1,6]-cyclization reaction was developed to achieve the modifications of indolenines.Based on the efficient strategy,a series of novel structural indolenine-tetrahydroquinoline assembly was synthesized with high diastereoselectivity from indolenine and o-substituted aminobenzaldehyde.5)A new BF3·Et2O catalyzed tandem[1,5]-hydride transfer/[1,6]-cychzation reaction was developed to achieve the modification of anthrones with N-heterocycles.Based on the highly efficient strategy,a series of novel spiro[indolizidine-anthrone]derivatives were synthesized from o-substituted amino cinnamyl anthrone.6)A new catalyst-free and operationally simple reaction with tandem condensation/[1,5]-hydride transfer/[1,6]-cyclization process was developed to achieve the modification of coumarins with N-heterocycles.Based on the efficient strategy,a series of novel spiro[quinolizidine-coumarin]derivatives(61-91%)were synthesized with high diastereoselectivity from 4-hydroxycoumarin and o-substituted aminobenzaldehyde. |
