Palladium(II)-Catalyzed Oxidative Carbocyclization: Stereoselective Formation of C–C and C–B Bonds
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Transition metal catalysis has emerged as one of the most versatile methods for the selective formation of carbon–carbon and carbon–heteroatom bonds. In particular, oxidative carbon–carbon bond forming reactions have been widely studied due to their atom economic feature. This thesis has been focused on the development of new palladium(II)-catalyzed carbocyclization reactions under oxidative conditions.
The first part of the thesis describes the palladium(II)-catalyzed oxidative carbocyclization-borylation and -arylation of enallenes. In these reactions, the (σ-alkyl)palladium(II) intermediate, which was shown previously to undergo β-hydride elimination, could be trapped in situ by organoboron reagents (B2pin2 and arylboronic acids) to form new carbon–boron and carbon–carbon bonds. Through these two protocols, a range of borylated and arylated carbocycles were obtained as single diastereomers in high yields.
The second part deals with a palladium(II)-catalyzed oxidative diarylative carbocyclization of enynes. The reaction was proposed to start with a syn-arylpalladation of an alkyne, followed by insertion of the coordinated alkene. Subsequent arylation afforded a series of valuable diarylated tetrahydrofuran and tetrahydropyran products.
The final part of the thesis advances the previously developed palladium(II)-catalyzed oxidative carbocyclization-borylation of enallenes in an enantioselective manner. C2-symmetric chiral phosphoric acids were used as the novel co-catalyst to trigger the enantioselective formation of intramolecular carbon–carbon bonds. By using this chiral anion strategy, a number of enallenes were converted to the borylated carbocycles with high to excellent enantioselectivity.
Place, publisher, year, edition, pages
Stockholm: Department of Organic Chemistry, Stockholm University , 2014. , 72 p.
Carbocyclization, Palladium catalysis, Oxidation, Enallenes, Enynes, Borylation, Arylation, Asymmetric Catalysis, Chiral Brønsted acids, Chiral anion
Research subject Organic Chemistry
IdentifiersURN: urn:nbn:se:su:diva-108669ISBN: 978-91-7649-020-4OAI: oai:DiVA.org:su-108669DiVA: diva2:759895
2014-12-05, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 14:00 (English)
Widenhoefer, Ross, Professor
Bäckvall, Jan-Erling, Professor
At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.2014-11-132014-10-312014-11-21Bibliographically approved
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