Rhodium Catalyzed Coupling of In Situ Generated Alpha-Lactams with Indoles and Synthesis and Surface Immobilization of Bis-Corannulene Molecular Receptors
Kumarasinghe, K. G. Upul Ranjan
Mead, Keith T.
Foster, Stephen C.
Mlsna, Todd E.
The first section of this dissertation (Chapter I-III) describes the development of new methodologies for the rhodium catalyzed C-N bond formation between sp3 hybridized carbon atom of phenyl substituted alpha-lactams and the nitrogen atom of indole derivatives. Phenyl substituted alpha-lactams generated in situ from the corresponding alpha-bromoamides reacted with indoles in the presence of rhodium catalyst to afford the ring opening products of alpha-lactams. The scope of this methodology was extended to various types of indole derivatives including electron donating and withdrawing substituents. Furthermore, a series of functionalized phenyl substituted alpha-lactams generated in situ reacted with indole to assess the viability of this methodology. The developed method provides an atom-economical approach for the formation of substituted alpha-amino amides in good to excellent yields. The main goal of the research described in the second section (Chapter IV-VII) is the synthesis of the corannulene-based molecular receptors with polar tethers and their immobilization on silica gel. First, we have considered a preparation of bis-corannulenoanthracene, formally possessing the pentacene core as a potential precursor for a series of barrelene based bis-corannulene receptors with polar groups. Bis-corannulenoanthracene was synthesized by the double Diels-Alder cycloaddition of isocorannulenofuran with bis-benzyne precursor, followed by deoxygenation of the endoxide adducts. While bis-corannulenoanthracene is stable enough to be isolated and stored, its pentacene core undergoes facile cycloaddition with maleic anhydride to afford bis-corannulene molecular receptor with the barrelene tether adorned with the anhydride moiety. The 1H NMR titration experiments carried out in chlorobenzene-d5 proved the high binding affinity of the receptor toward C60. In addition, the presence of polar anchors on its tether allowed for its deposition on silica gel through the (3-aminopropyl)triethoxysilane linker.