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New C-H activations and cross-coupling reactions for modification of deazapurine nucleobases
Sabat, Nazarii ; Hocek, Michal (advisor) ; Tobrman, Tomáš (referee) ; Hlaváč, Jan (referee)
This PhD thesis reports the development of novel C-H activation strategies and aqueous-phase Suzuki-Miyaura cross-coupling reactions for the synthesis of modified deazapurine nucleobases. The methodologies of chemo- and regioselective synthesis of highly functionalized deazapurines have been developed by using modern C-H activation chemistry. Various functional groups such as amino-, imido-, silyl- and phosphonyl- were introduced by C-H activation reactions. Amino deazapurine derivatives were synthesized by developed Pd/Cu-catalyzed direct C-H amination and C-H chloroamination of 6-substituted 7-deazapurines with N-chloro-N- alkyl-arylsulfonamides. C-H imidation reactions of pyrrolopirimidines were performed under ferrocene catalysis with N-succinimido- or N-phtalimidoperesters. In order to obtain silylated derivatives, Ir-catalyzed C-H silylations of phenyldeazapurines with alkyl silanes were designed. Highly interesting deazapurine phosphonates were prepared by using Mn-promoted C-H phosphonation method and were further transformed into the corresponding phosphonic acids. All of the developed direct C-H functionalization reactions proceeded regioselectively at position 8 in deazapurine core, except for C-H silylation where reaction undergoes mainly as directed ortho C-H silylation on phenyl ring,...
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Cyclotrimerization of alkynes and nitriles in the synthesis of helically chiral compounds
Klívar, Jiří ; Stará, Irena (advisor) ; Tobrman, Tomáš (referee)
The objective of this Thesis was to prepare dialkynenitriles 156 and 168 for the synthesis of aza[6]helicene 146 and 147 via intramolecular [2+2+2] co-cyclotrimerization. It was found that it is possible to use co-cycloisomerization of alkynedinitriles 182, 187, 192 and 195, a reaction so far not described in the literature, for the preparation of dibenzodiazahelicenes 148 and 149 and dioxadiazahelicenes 150 and 151 possessing a pyridazine subunit. Moreover, alkynedinitriles 152, 153, 154 and 155 were synthesized to further study of this co-cycloisomerization reaction. The Theoretical Part outlines some representative examples of methods for the preparation of azahelicenes and azoniumhelicenes, current development of [2+2+2] cocyclotrimerization in the synthesis of pyridine derivatives and methods of pyridazine synthesis. The syntheses of dialkynenitriles 156 a 168, diazahelicenes 148, 149, 150, 151 and alkynedinitriles 152, 153, 154 and 155 are described in the section Results and Discussion and Experimental Part.
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The Combination of Organometallic, Transition-Metal Catalyzed, Radical and Carbocationic Reaction Steps to Domino Processes
Jagtap, Pratap Ramling ; Jahn, Ullrich (advisor) ; Tobrman, Tomáš (referee) ; Bureš, Filip (referee)
This work deals with the development of methodology, which couples reactive intermediates of varying oxidation states, in tandem sequences comprising 1,2-organometallic addition/transition metal catalyzed isomerization/Michael addition/SET oxidation/radical cyclization/oxygenation steps in the synthesis of highly functionalized carbocycles. Implementation of this sequence being catalytic in the SET oxidant was studied. 1,4-Diketones were synthesized in a tandem 1,2-addition/ruthenium-catalyzed redox isomerization/enolates oxidation/radical dimerization reaction and results were compared with 1,4-diketones formation via oxidative coupling of ketone enolates. The total synthesis of selective tetrahydrofuran lignans from 1,4-diketones obtained in a tandem addition/isomerization/dimerization reaction is also documented
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