Thesis

The search for radicals in unexpected places

Creator

Clark, Kenneth Forbes

Rights statement

Strathclyde Thesis Copyright

Awarding institution

University of Strathclyde

Date of award

2022

Thesis identifier

T16495

Person Identifier (Local)

201869783

Qualification Level

Doctoral (Postgraduate)

Qualification Name

Doctor of Philosophy (PhD)

Department, School or Faculty

Department of Pure and Applied Chemistry

Abstract

In the last century, many literature reports discuss the electron-transfer from simple alkoxides, in particular NaOtBu and KOtBu, to aryl halides. These reports are controversial with many providing evidence on the contrary. This thesis will initial focus on explaining the role of these alkoxides in the transformations and reports on mechanistic investigations. Heating 9-bromoanthracene I with KOtBu yields 6 principal products (II-VII), all of which can be explained through radical chemistry (Scheme 1). Additionally, methylated compounds (V, VIII-X) are formed which are shown to result from the addition of methyl radicals (formed after electron transfer from tert-butoxide and subsequent collapse of the tert-butoxyl radical) to arenes. These are the first examples of alkylated arenes resulting from the collapse of alkoxyl radicals in the BHAS reaction and is undisputable evidence of electron transfer from KOtBu. Characterisation of the BHAS reaction with iodoarene XI was then significantly studied and was shown to provide important information about mechanism (Scheme 2). The experiments additionally demonstrated that substrate XI could be utilised as a stringent assay for xylyl radicals. Finally, determination of radical intermediates in organometallic reactions (e.g. Ni, Pd, Cu) can be challenging. A strict assay that allows for clear identification of aryl radical intermediates is required. Using substrate XI as an assay, organopalladium conditions that promote radical pathways were investigated and systems that direct to a radical route were disclosed (Scheme 3). [See thesis for schemes illustrations]

Advisor / supervisor

Murphy, John A., 1948-

Resource Type

Doctoral thesis

Note

Previously held under moratorium from 15th February 2023 until 15th February 2025.

DOI

10.48730/kajn-bf90

Funder

Embargo Note

This thesis is restricted to Strathclyde users only until 15th February 2028.

Relazioni

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