REGIOSELECTIVE RING OPENING REACTIONS OF AZIRIDINE-2-PHOSPHONATES AND AZIRIDINE BASED CHIRAL LIGANDS FOR CATALYTIC, ASYMMETRIC AZOMETHINE YLIDE CYCLOADDITIONS AND AZA-HENRY REACTION

2021-7-16
Beksultanova, Nurzhan
Show full item record
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
296
views
705
downloads
Aziridines are small three-membered heterocyclic compounds. They are important as building blocks for many nitrogen-containing biologically active compounds and as chiral ligands in metal catalyzed asymmetric synthesis of different organic compounds. In the first part of this thesis, we have studied the ring opening reactions of various racemic and chiral aziridine-2-phosphonates. Regioselective aziridine ring opening reaction with HCl formed -amino--chlorophosphonates in 60-95 % yield and the same reaction with alcohols in the presence of H2SO4 formed -amino--alkoxyphosphonates in 35-91 % yield. In the second part of this thesis, we have studied the catalytic performance of aziridine based chiral ligands with a transition metal for 1,3-dipolar cycloaddition (1,3-DC) reaction of azomethine ylides with electron deficient dipolarophiles for the synthesis of highly substituted pyrrolidine derivatives. As the vi aziridine based chiral ligands our group synthesized a small library of ferrocenyl aziridinyl methanol (FAM) chiral compounds and tested their catalytic performance in different reactions. After screening different transition metals and 12 FAM ligands, it was found that Ag-CFAM4 catalyst system forms pyrrolidine derivatives in up to 95% yield with 99 % ee via the 1,3-DC reaction of azomethine ylides. Finally, we have also tested the catalytic performance of FAM ligands for the aza-Henry reaction which is another important C-C bond-forming process in Organic Chemistry. Optimization studies for this reaction showed that Zn-PFAM1 catalyst system works better for the addition of nitroalkanes to Boc-substituted imines to give the expected products in up to 88 % yield with 71% ee.
Aziridine-2-phosphonates, regioselective ring opening, chiral catalysts, 1,3-dipolar cycloaddition, aza-Henry reaction.
https://hdl.handle.net/11511/91675
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

SYNTHESIS OF NEW AZIRIDINE DERIVATIVES AS POTENTIAL PIPERAZINE PRECURSORS
Bayat, Duygu; Doğan, Özdemir; Department of Chemistry (2022-7-19)
Aziridines are three-membered heterocyclic compounds. They have significant properties in organic chemistry and medicinal chemistry. Many natural products have aziridines as medicines to treat various disorders. Especially, they are essential intermediates in the synthesis of heterocyclic frameworks. Moreover, aziridines can be easily transformed into diverse types of biologically active compounds. Other remarkable heterocyclic compounds are piperazines, known as six-membered rings with two nitrogen atoms a...
Enantioselective Friedel-Crafts alkylation of indole with nitroalkenes in the presence of bifunctional squaramide organocatalysts
Dündar, Esra; Tanyeli, Cihangir (2021-01-01)
A series of chiral bifunctional quinine and 2-aminoDMAP based squaramide organocatalysts are evaluated in Friedel-Crafts alkylation of indoles with nitroolefins. These 3-substituted indole derivatives are synthesized in the presence of sterically encumbered tert-butyl squaramide/quinine with high enantioselectivity (up to >99% ee) and moderate chemical yields (up to 80%) by representing as chiral precursors for very important biologically active molecules. Besides, this asymmetric transformation provides a ...
ENANTIOSELECTIVE OXIDATION OF THIOANISOLE TO METYL PHENYL SULFOXIDE BY CHIRAL COMPOUNDS BEARING N-Cl BOND
İPEK, HALİL; Akdağ, Akın (Informa UK Limited, 2015-08-03)
Chiral sulfoxides are used in asymmetric synthesis and are present in various biologically active compounds. Asymmetric synthesis of the sulfoxides has been performed by chiral metal complexes and non-metals containing peroxide and oxide moieties. In this study, a new metal free method has been developed to oxidize thioanisole into methyl phenyl sulfoxide with easily accessible chiral compounds carrying N-Cl bond. For this purpose, chiral amine and amide bearing reagents were synthesized and chlorinated by ...
Regioselectivity observed in manganese(III) acetate mediated addition of acetylacetone to various alkenes: mechanistic and theoretical studies
Ceyhan, Selin; Cetinkaya, Yasin; Akdağ, Akın; BALCI, METİN (2016-10-27)
Various alkenes substituted at the 1,2-positions by 2-thiophenyl, 3-thiophenyl, and phenyl substituted by electron-withdrawing and electron-donating groups were treated with acetylacetone in the presence of Mn(OAc)(3) in acetic acid. In cases where the thiophene ring was connected at the C-2 carbon atom to the double bond, a single regioisomer was formed whereas in case of substitution at the C-3 positions two regioisomers were formed. Stilbene derivatives also gave two regioisomers under the same reaction ...
Enantioselective Michael Addition of Nitroalkanes to Nitroalkenes Catalyzed by Chiral Bifunctional Quinine-Based Squaramides
KANBEROĞLU, Esra; Tanyeli, Cihangir (2016-01-01)
A family of chiral bifunctional acid-/base-type quinine/squaramide organocatalysts is shown to be highly active promoters of the conjugate addition of 1-nitropropane to various trans--nitroalkenes. The cooperation of the quinine and the sterically encumbered squaramide moieties catalyzed the Michael addition reactions at 0 degrees C by using a catalyst loading of only 2mol% to afford the 1,3-dinitro Michael adducts with excellent enantioselectivity and diastereoselectivity (up to 95%ee and syn/anti isomers ...
Citation Formats
N. Beksultanova, “REGIOSELECTIVE RING OPENING REACTIONS OF AZIRIDINE-2-PHOSPHONATES AND AZIRIDINE BASED CHIRAL LIGANDS FOR CATALYTIC, ASYMMETRIC AZOMETHINE YLIDE CYCLOADDITIONS AND AZA-HENRY REACTION,” Ph.D. - Doctoral Program, Middle East Technical University, 2021.
METU IIS - Integrated Information Service open@metu.edu.tr