Rh(?)-catalyzed C-H Activation Synthesis Of Heterocyclic Compounds

Transition-metal-catalyzed C-H functionalization has been explored for building desired valuable C-C/C-hetero bonds or heterocycle skeletons and also has made remarkable achievements in promoting the development of new reaction system and the research of catalytic mechanism.These studies have combined a series of metal organic chemical radical reactions and catalytic systems to develop a series of new C-H functionalization system.In this paper,synthesis of heterocyclic structures via rhodium(?)catalyzed C-H functionalization was studied.The main contents include:In the first chapter,we simply introduce the current development situation of Rh-catalyzed C-H bond activation.In the second chapter,Rh(?)-catalyzed,N-nitrosodirected C-H activation allows the development of a traceless,atom-and step-economic,cascade approach for the synthesis of indole skeletons,starting from readily available N-nitroso and ?-diazo-?-keto compounds.A distinct C-H activation-based traceless synthetic protocol via electrophilic removal of a directing group is reported,complementing the currently exclusively used nucleophilic strategy.Importantly,the cyclization/denitrosation reaction represents a hitherto unobserved reactivity pattern for the N-nitroso group.In the third chapter,we report synthesis of isoquinolines based on efficient C-C and C-N bond formation through Rh(?)-catalyzed C-H activation and subsequent intramolecular cyclization is reported.Diazodiesters serving as a C2 source in the newly formed heterocycles are first demonstrated.Additionally,the Rh(?)-catalyzed direct C-H activation/cyclization of benzimidates with diazoketoesters is also described.In the fourth chapter,we report an efficient double C-N bond formation sequence to prepare highly substituted quinazolines utilizing benzimidates and dioxazolones under the catalytic redox-neutral[Cp*RhCl2]2/AgBF4 system,where dioxazolones could work as an internal oxidant to maintain the catalytic cycle,is reported.N-unsubstituted imine not only acts as a directing group but also functions as a nucleophile in postcoupling cyclization,and dioxazolone acts as a coupling partner for access to heterocycle.In the fifth chapter,we report the discovery of N-tert-butyloxycarbonyl(N-Boc)cleavage as a versatile reactivity paradigm for diverse C-H activation-initiated reactivity relay cascades.Rh(?)-catalyzed coupling of N-Boc hydrazone/N-Boc hydrazine with diazodiester/diazoketoester provides efficient access to a synthetically and medicinally important class of compounds,N-amino azaheterocycles,including N-amino isoquinolin-3-ones,N-amino indoles,and N-amino isoquinoliniums.In addition,bifurcation of reactivity relay cascades allows the synthesis of benzodiazepines.In the sixth chapter,we report herein a redox-neutral Cp*Co(?)-catalyzed cyclization of acetophenone N-Boc hydrazones with alkynes for streamlined synthesis of isoquinolines,accomplished via formation of a C-C and a C-N bond along with N-N bond cleavage.Moreover,this rapid approach can be completed in 30 min with yields up to 85%.