Catalytic Stereodivergent Synthesis of Atropisomeric Multiaxis Systems and their Application in Electron Transfer Studies and Ligand Design

Castrogiovanni, Alessandro. Catalytic Stereodivergent Synthesis of Atropisomeric Multiaxis Systems and their Application in Electron Transfer Studies and Ligand Design. 2021, Doctoral Thesis, University of Basel, Faculty of Science.


Official URL: https://edoc.unibas.ch/82838/

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A well-defined spatial orientation of substituents in a molecular framework is an essential requirement for the synthesis of molecular systems with unique properties and applications. Due to their configurational stability, oligo-1,2-naphthylenes are particularly suitable to organize groups in space, and a method that controls the configuration of each stereogenic axis is thus highly desirable. The thesis outlines our approach for the stereodivergent synthesis of atropisomeric multiaxis systems, based on the sequential addition of a building block to aromatic aldehyde precursors, followed by an in situ double oxidation and stereoselective arene-forming aldol condensation. In order to overcome the substrate bias and divert atropodiastereoselectivity, efficient amine and ion-pairing catalysts were identified and four stereogenic axes could be individually controlled.
The distinct topology of the oligomers obtained and their reduced conformational freedom, made them particularly suitable for photoinduced electron transfer (PET) studies. Upon functionalization of the corresponding atropisomeric multiaxis naphthaldehydes, three donor-acceptor Ru(II) complexes have been synthesized and their distance-dependent PET properties have been evaluated.
During the past years, monophosphines have seen an increased importance in homogenous catalysis, due to their characteristics that differentiate them from their bidentate counterparts. The crescent need of monodentate ligands with unique structural features, prompted us to design and synthesize JoyaPhos, an atropisomeric teraryl monophosphine ligand. The synthesis takes advantage of the stereoselective aldol condensation and of the direct ester-to-arene transformation developed in our group, for the de novo construction of the phenyl-naphthalenyl skeleton and the installation of the side anthracenyl group. Three JoyaPhos ligands with diverse stereoelectronic properties on the phosphine moiety have been synthesized and their activity and selectivity were essayed on different Au(I) and Pd(0)-catalyzed transformations.
Atroposelective Synthesis of N-Arylindoles:
Despite the plethora of methodologies for the synthesis of atropisomers with C-C stereogenic axes, the atroposelective construction of the C-N bond is not as straightforward, and novel catalytic methods able to address this challenge are still needed. In particular, the catalytic atroposelective synthesis of indoles featuring a C-N stereogenic axis is limited to few examples. For this reason, we investigated five different methodologies to access N-arylindoles atroposelectively under mild catalytic conditions via C-C, or C-N bond formation, one of which showing a preliminary and promising e.r. of 68:32.
Advisors:Sparr, Christof and Baudoin, Olivier and Mazet, Clément
Faculties and Departments:05 Faculty of Science > Departement Chemie > Chemie > Organische Chemie (Sparr)
UniBasel Contributors:Sparr, Christof and Baudoin, Olivier
Item Type:Thesis
Thesis Subtype:Doctoral Thesis
Thesis no:14104
Thesis status:Complete
Number of Pages:v, 229
Identification Number:
  • urn: urn:nbn:ch:bel-bau-diss141043
edoc DOI:
Last Modified:25 Jun 2021 04:30
Deposited On:24 Jun 2021 09:14

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