Murray State Theses and Dissertations

Abstract

Nucleophilic phosphine catalysis has demonstrated its value in synthetic chemistry by allowing for mild carbon-carbon bond formation. Many phosphine-catalyzed reactions with electron-deficient alkynes have been reported in recent years, leading to an array of valuable products. Stemming from this field of study, phosphines can also be utilized as mild chemoselective reductants for alkynes, resulting in the corresponding alkenes. Herein, a mild, stereoselective, phosphine-mediated partial reduction of alkynes to (E)- and (Z)-alkenes is described. Specifically, a general method for the partial reduction of ynoates to the corresponding (E)- and (Z)-enoate, and ynones to the corresponding (E)-enones has been developed. Furthermore, it has been demonstrated that ynones can stereoselectively arrive at (Z)-enones through the careful examination and tuning of phosphines; however, fully optimized conditions are still being explored.

In addition to this work, a phosphine-catalyzed annulation was investigated, and showed the potential to form dihydro-1,2-oxazines starting from ynones and nitrones. Another redox strategy for carbon-carbon bond formation was also researched, incorporating an iron-catalyst that facilitated hydrogen transfers through an intramolecular process. From this strategy, a three-component, “one-pot” 1,3-amino alcohol synthesis was explored, employing the Mannich reaction and using readily available starting materials.

Year manuscript completed

2019

Year degree awarded

2019

Author's Keywords

Phosphine-Mediated, Reduction, Alkynes, Catalysis, Stereoselective

Thesis Advisor

Rachel E Whittaker

Committee Chair

Kevin M Miller

Committee Member

Kevin Revell

Committee Member

Rachel Allenbaugh

Committee Member

Kasey Clear

Document Type

Thesis

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