Chemistry, Department of

 

First Advisor

Jian Zhang

Date of this Version

Fall 12-13-2019

Citation

Armada, Nicholas. C(sp2)-C(sp3) Cross-Coupling of Aryl Halides and Active C(sp3)-H Bonds via Dual Catalysis: Organic Photocatalysis/Nickel Redox Catalysis. M.S. Thesis, University of Nebraska-Lincoln: Lincoln, NE, 2019

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska in Partial Fulfillment of the Requirements For the Degree of Master of Science, Major: Chemistry, Under the Supervision of Professor Jian Zhang. Lincoln, Nebraska: December, 2019

Copyright 2019 Nicholas Armada

Abstract

Convenient catalytic methodologies that can facilitate the formation of C-C bonds are undoubtedly of great interest in synthetic organic chemistry. Recent reports in literature have showcased hybrid catalytic methods that couple Ni-redox catalysis and photocatalysis to enable C-H activation of tetrahydrofuran (THF) and subsequent cross-coupling with aryl halides in appreciable yields and under relatively mild reaction conditions.1-2 However, these studies used expensive, heavy metal-containing photocatalysts and both report difficulty obtaining low-specificity across their scopes of aryl-halides. The following report will shed light on a class of photo-excitable small organic molecules that – in conjunction with a catalytic Ni-redox cycle – can be used to catalyze C-C cross-coupling reactions between THF and aryl chlorides, bromides, and iodides with yields comparable to the aforementioned reports. After screening several organic molecules with suspected photoactivity and optimization of the reaction conditions, several benzophenone derivatives were found to catalyze the cross-coupling reaction in yields up to 97%. Mechanistic investigations suggest that this reaction proceeds through a tandem catalytic pathway that involves a photocatalyzed hydrogen atom transfer/proton-coupled electron transfer (HAT/PCET) process and a Ni-mediated oxidative addition/reductive elimination cross-coupling process.

Advisor: Jian Zhang

Share

COinS