Stereoselective addition of terminal alkynes to oxocarbenium and iminium ions
| Author(s) | Liu, Jixin | |
| Date Accessioned | 2017-06-28T11:16:48Z | |
| Date Available | 2017-06-28T11:16:48Z | |
| Publication Date | 2016 | |
| Abstract | This dissertation focuses on investigations of stereoselective additions of terminal alkynes to oxocarbenium and iminium ions. Chapter 1 describes the development of mild reaction conditions for the addition of unfunctionalized, terminal alkynes to a-halo oxocarbenium ions, formed in situ from acetal precursors. When coupled with bromination to form a β-halo acetal intermediate, this method enables the preparation of difunctionalized oxygen heterocycles from simple enol ether precursors in excellent diastereoselectivities. ☐ Chapter 2 describes our studies towards the development of alkynylation conditions to make C-glycoside. This reaction provides alkynylated 2-deoxy sugars in synthetically useful yield and excellent diastereoselectivity. The alkynylation utilizes an unfunctionalized alkyne and readily available protected sugar substrates. ☐ Chapter 3 focuses on the development of a copper-catalyzed alkynylation of 1-aryl isoquinolinium ions that delivers cyclic α-diaryl tetrasubstituted amines in good yields and high enantioselectivities. This reaction employs a catalyst with commercially available components, and tolerate a wide range of isoquinolines and alkynes. Mechanistic studies suggest an aggregated Cu/Ph-PyBox complex may act as the active catalyst. ☐ Overall, this dissertation describes my efforts towards developing methodology for the selective addition of terminal alkynes to reactive cationic intermediates, including oxocarbenium ions and iminium ions. | en_US |
| Advisor | Watson, Mary P. | |
| Degree | Ph.D. | |
| Department | University of Delaware, Department of Chemistry and Biochemistry | |
| DOI | https://doi.org/10.58088/86ax-8w72 | |
| Unique Identifier | 993260377 | |
| URL | http://udspace.udel.edu/handle/19716/21510 | |
| Publisher | University of Delaware | en_US |
| URI | https://search.proquest.com/docview/1868510640?accountid=10457 | |
| dc.subject.lcsh | Alkynes. | |
| dc.subject.lcsh | Oxocarbenium ions. | |
| dc.subject.lcsh | Iminium ions. | |
| dc.subject.lcsh | Glycosides. | |
| dc.subject.lcsh | Copper catalysts. | |
| Title | Stereoselective addition of terminal alkynes to oxocarbenium and iminium ions | en_US |
| Type | Thesis | en_US |