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
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.

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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.