Date of Award
Winter 12-15-2017
Degree Name
Doctor of Philosophy (PhD)
Degree Type
Dissertation
Abstract
Two new cascade transformations of α,β-unsaturated thioesters catalyzed by amidine-based catalysts have been developed. First, a reagent-free transformation of o-formylaryl cinnamoyl thioesters catalyzed by HBTM-2 to produce 2-substituted thiochromenes achieved high enantioselectivities and yields while forming carbon dioxide as the only byproduct. Second, a highly diastereo- and enantioselective tandem rearrangement of less reactive enone thioesters into tricyclic thiochromanes in the presence of electron-rich amidine-based catalysts was developed. These catalysts were designed with the help of DFT calculations. H-PIP, the first chiral amidine-based catalyst synthesized in our group, performed the best overall in the thiochromane synthesis.
The second chapter of this thesis describes the design of chiral ligands using the Cl-PIQ structure as a building block. A new class of fused imidazoline ligands was synthesized from 2-chloro-3-quinolinecarboxaldehyde, and their efficacy was demonstrated by their performance in the asymmetric Henry reaction.
Language
English (en)
Chair and Committee
Vladimir B. Birman
Committee Members
Jonathan C. Barnes, Alexei V. Demchenko, Liviu M. Mirica, Kevin D. Moeller,
Recommended Citation
Ahlemeyer, Nicholas Alan, "New Ventures in Amidine-Based Catalyst Design" (2017). Arts & Sciences Electronic Theses and Dissertations. 1200.
https://openscholarship.wustl.edu/art_sci_etds/1200
Comments
Permanent URL: https://doi.org/10.7936/K71R6PXS