Towards a Catalytic Asymmetric Cope Rearrangement and the Synthesis and Self-Assembly of Metal-Coordinated Hosts
- Author(s): Moehlig, Melissa Padilla
- Advisor(s): Hooley, Richard J
- et al.
The Cope rearrangement has been used as the key step of several natural products but to date there is only one limited example in the literature that is capable of performing an asymmetric variant of this reaction. The first half of this dissertation focuses on our efforts towards performing a catalytic asymmetric Cope rearrangement to access remote stereocenters. The rearrangement of 2-formyl-1,5-dienes was achieved with both Brønsted and Lewis acid catalysts. The best Lewis acid catalyst was determined to be gold(III)chloride. As there are no examples of asymmetric Au(III) catalysis, we designed and synthesized bis-alpha-chiral dipyrromethanes as potential new ligands for organometallic asymmetric Cope rearrangements.
This work also focuses on the design and synthesis of functionalized deep cavitands for use as biomimetic C-H oxidation catalysts. Enzymes are capable of performing site-selective oxidations by incorporating substrates in their binding pockets and selectively oxidizing the C-H bond closest in proximity to the active site of the enzyme. Cavitands are capable of selectively binding guests of the appropriate size and shape, much like enzymes. Specifically, this work involves the synthesis of cavitands that contain deep cavities with functionalized rims that possess the ability to complex to metals such as iron or copper. These deep functionalized cavitands were found to be capable of binding amines and other small guests as well as performing unprecedented anion binding. Metal coordination was also achieved at the rims of the cavitand making these metallobound cavitands potential enzymes mimics by binding a guest in its cavity and selectively oxidizing the groups closest in proximity to the catalytic site, i.e. the metal bound rims.