| dc.contributor.advisor | Alcarazo, Manuel Prof. Dr. | |
| dc.contributor.author | Böhm, Marvin Jeldrik | |
| dc.date.accessioned | 2020-12-21T13:45:28Z | |
| dc.date.available | 2020-12-21T13:45:28Z | |
| dc.date.issued | 2020-12-21 | |
| dc.identifier.uri | http://hdl.handle.net/21.11130/00-1735-0000-0005-152E-1 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-8378 | |
| dc.identifier.uri | http://dx.doi.org/10.53846/goediss-8378 | |
| dc.language.iso | eng | de |
| dc.publisher | Niedersächsische Staats- und Universitätsbibliothek Göttingen | de |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc-nd/4.0/ | |
| dc.subject.ddc | 540 | de |
| dc.title | Synthesis and reactivity of succinylthioimidazolium salts: A unified strategy for the preparation of thioethers | de |
| dc.type | doctoralThesis | de |
| dc.contributor.referee | Ackermann, Lutz Prof. Dr. | |
| dc.date.examination | 2020-12-14 | |
| dc.description.abstracteng | Sulfur is one of the main group elements on our planet with a natural abundance of
(0.46±0.15)w%. In its most common allotropic form sulfur is a yellow powder and exhibits a
cyclic S8 structure. Apart of the cyclic S8 form, several smaller and larger ring allotropes of Sn
with n = 6 to 20 have been isolated. Aside from its natural occurrence as the pure element,
sulfur is also forming inorganic salts like sulfides, sulfates, or sulfites. Moreover, sulfur plays
an important role in the field of organic chemistry and biochemistry.[2] In this regard various
sulfur-containing functional groups with different oxidation states of the sulfur atom, e.g. thiols
(+II), disulfides (+I), sulfoxides (+IV) and sulfones (+VI) and thioethers (+II), are known.Especially aryl thioethers are predominantly important representatives of sulfur containing
functional groups in organic chemistry because of their appearance in key scaffolds of
pharmaceutical important compounds, natural products, in the field of material science as well
as in the field of ligand design.
Additionally, aryl thioethers, also known as aryl sulfides, are a versatile synthetic platforms
because they can be easily converted in a variety of other functional groups and find also
applications as directing groups in chemistry of C–H functionalization.
Due to the significant importance of this compound class, this work focuses on the
development of a transition metal free and highly modular protocol for the synthesis of a wide
range of different unsymmetrically substituted aryl thioethers. Furthermore, the developed
concept is used to access further sulfur-containing compounds as (arylthio)sulfonamides. In the presented thesis, a highly modular protocol for the transition metal-free preparation of
diaryl and alkyl aryl sulfides was accomplished as a significant contribution to the area of
sulfide synthesis. For this purpose, imidazole-2-thione-derived sulfenylation reagents were developed. It was shown that their versatile reactivity allowed the initial activation of
several unfunctionalized (hetero)arenes. Additionally, the protocol demonstrated a high
functional group tolerance. Hereby, the influence of the sulfur-containing
thiourea backbone as well as the effect of the electron-withdrawing N-succinimidyl moiety in
the reagents was studied. In a consecutive step, metal organyls were identified as suitable
nucleophiles for the synthesis of aryl sulfides from a cationic intermediate which were
isolated in moderate to excellent yields.
The presented reagent can be considered as a synthetic equivalent of a [S]2+ synthon which
undergoes a double electrophilic attack. Noteworthy, the herein developed protocols allow the
sequential twofold sulfenylation of electron-rich heterocycles like N-phenylpyrrole. In addition,
several cationic intermediates were crystallized and analyzed by X-ray crystallography to
verify their molecular connectivity. The general methodology was further extended toward the
synthesis of unsymmetrical aryl selenides. Based on these results, an efficient single step protocol for the synthesis of imidazolyl and
further heterocyclic thioethers was elaborated. With this, further diheteroaryl sulfides were
synthesized in yields of up to 82% from the in situ formed reagents. | de |
| dc.contributor.coReferee | Stalke, Dietmar Prof. Dr. | |
| dc.contributor.thirdReferee | Frauendorf, Holm Dr. | |
| dc.contributor.thirdReferee | Koszinowski, Konrad Prof. Dr. | |
| dc.contributor.thirdReferee | Walker, Johannes C. L. Prof. Dr. | |
| dc.subject.eng | transition metal free | de |
| dc.subject.eng | arylsulfide | de |
| dc.subject.eng | organic chemistry | de |
| dc.subject.eng | electrophilic sulfenylation | de |
| dc.subject.eng | mechanistical studies | de |
| dc.subject.eng | imidazolthioether | de |
| dc.subject.eng | late-stage-functionalization | de |
| dc.identifier.urn | urn:nbn:de:gbv:7-21.11130/00-1735-0000-0005-152E-1-6 | |
| dc.affiliation.institute | Fakultät für Chemie | de |
| dc.subject.gokfull | Chemie (PPN62138352X) | de |
| dc.identifier.ppn | 1743472439 | |