Diaryliodonium Salts: Development of Synthetic Methodologies and α-Arylation of Enolates
2011 (English)Doctoral thesis, comprehensive summary (Other academic)
This thesis describes novel reaction protocols for the synthesis of diaryliodonium salts and also provides an insight to the mechanism of α-arylation of carbonyl compounds with diaryliodonium salts.
The first chapter gives a general introduction to the field of hypervalent iodine chemistry, mainly focusing on recent developments and applications of diaryliodonium salts.
Chapter two describes the synthesis of electron-rich to electron-poor diaryliodonium triflates, in moderate to excellent yields from a range of arenes and iodoarenes.
In chapter three, it is described that molecular iodine can be used together with arenes in a direct one-pot, three-step synthesis of symmetric diaryliodonium triflates. A large scale synthesis of bis(4-tert-butylphenyl)iodonium triflate is also described, controlled and verified by an external research group, further demonstrating the reliability of this methodology.
The fourth chapter describes the development of a sequential one-pot synthesis of diaryliodonium salts from aryl iodides and boronic acids, furnishing symmetric and unsymmetric, electron-rich to electron-poor diaryliodonium tetrafluoroborates in moderate to excellent yields. This method was developed to overcome the regiochemical limitations imposed by the reaction mechanism in the protocols described in the preceding chapters.
Chapter five describes a one-pot synthesis of heteroaromatic iodonium salts under similar conditions described in chapter two.
The final chapter describes the reaction of enolates with chiral diaryliodonium salts or together with a phase transfer catalyst yielding racemic products. DFT calculations were performed, which revealed a low lying energy transition state (TS) between intermediates, which is believed to be responsible for the lack of selectivity observed in the experimental work. It is also proposed that a [2,3] rearrangement is preferred over a [1,2] rearrangement in the α-arylation of carbonyl compounds.
The synthetic methodology described in this thesis is the most generally applicable, efficient and high-yielding to date for the synthesis of diaryliodonium salts, making these reagents readily available for various applications in synthesis.
Place, publisher, year, edition, pages
Stockholm: Department of Organic Chemistry, Stockholm University , 2011. , 88 p.
Hypervalent Iodine Compounds, One-Pot Synthesis, Regiospecific Synthesis, Aromatic Substitution, Aryl Iodides, Arenes, Boronic Acids, Heteroaromatics, Arylations, Reaction Mechanisms, Density Functional Calculations, Large Scale Synthesis
Research subject Organic Chemistry
IdentifiersURN: urn:nbn:se:su:diva-54738ISBN: 978-91-7447-233-2 (print)OAI: oai:DiVA.org:su-54738DiVA: diva2:403072
2011-04-15, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (English)
Togni, Antonio, Professor
Olofsson, Berit, Docent
List of papers