Synthesis of cycloheptadiene annelated dihydrofurane derivatives and design of pyrrolo-pyrrolo-pyrazines and α-alkylidyn-γ-butyrolactones via alkyne cyclization /

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2018
Aslanoğlu, Furgan
Owing to fascinating regiochemistry and controversial reaction mechanism, the oxidative free radical cyclization reaction of unsaturated bicyclic endoperoxides is an interesting area. In the first part of the thesis, we reacted various 1,3-dicarbonyl compounds with cycloheptatriene in the presence of Ce(NH4)2(NO3)6 to obtain dihydrocyclohepta[b]furan derivatives. Then, the formed 1,3-cycloheptadiene unit of dihydrocyclohepta[b]furan derivatives was reacted with singlet oxygen to give the corresponding bicyclic endoperoxides. Bicyclic endoperoxides which include acetyl group were reacted with CoTPP, AuCl3 and NEt3. Dihydrocyclohepta[b]furan derivatives were oxidized with SeO2 to tropone derivatives, biologically interesting molecule. In the second part of the thesis, a new synthetic method for the synthesis of pyrrolo- pyrrolo-pyrazine derivatives was developed. Firstly, pyrrole was reacted with 2-pyrrolidinone to generate 2,2'-(1'-pyrrolinyl)pyrrole, which was reacted with propargyl bromide derivatives to afford propargylated compounds which were further derivatized via Sonogashira cross coupling reaction. Pd/C-supported cyclization reactionof propargylated compounds and their derivative with Pd/C, afforded pyrrolo-pyrrolo-pyrazine derivatives. In the last part of the thesis, we examined the reaction of bicyclic endoperoxides with gold salt for the first time. Firstly, we synthesized bicyclic endoperoxide, 2,3-dioxabicyclo[2.2.2]oct-5-ene by the reaction of cyclohexa-1,3-diene with singlet oxygen. Reaction of unsaturated bicyclic endoperoxide with alkynes in the presence of Au(L)/AgOTf resulted in the formation of α-alkylidine-γ-butyrolacton derivatives.