Geraci, Gaetano (2024). Application of alpha-boryl radicals in ATRA reactions. (Thesis). Universität Bern, Bern
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Abstract
The common thread of this thesis is the application of alpha-boryl radicals in different ATRA (Atom Transfer Radical Addition) reactions. They were generated by using various types of initiators, but the most reliable and efficient was Et3B/DTBHN. The first part of the thesis is devoted to the application of alpha-boryl radicals in intermolecular ATRA reactions which delivered 1,3-iodo boronic esters as final products. The optimization of the conditions and a small scope on different linear olefines will be presented. The observed yields being moderate, we then decided to study the reaction on dienes, with the aim of better understanding the last step of the ATRA reaction, the Iodine Atom transfer. The choice of this unsaturated system was not random: when the alpha-boryl radical is added, they undergo 5-exo-trig cyclization and deliver 1,5-iodo boronic esters as products. We speculated that the relative position of iodine and boronic ester being different, the compounds would be more stable on silica than the parent 1,3-iodo boronic esters. This cascade reaction was renamed ATRAC (Atom Transfer Radical Addition and Cyclization). The synthesis and the reaction of different dienes with different radical precursor together with some investigations about the reactivity of alpha-boryl radicals will be detailed. Based on the knowledge acquired from the ATRAC project, a new annulation reaction using secondary alpha-boryl radicals was investigated. The scope and the limitations of the reaction will be presented. This new annulation reaction was renamed ATRAn (Atom Transfer Radical Annulation).
| Item Type: | Thesis |
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| Dissertation Type: | Single |
| Date of Defense: | 5 July 2024 |
| Subjects: | 500 Science > 540 Chemistry |
| Institute / Center: | 08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP) |
| Depositing User: | Hammer Igor |
| Date Deposited: | 03 Jul 2025 06:12 |
| Last Modified: | 03 Jul 2025 06:45 |
| URI: | https://boristheses.unibe.ch/id/eprint/6357 |
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