Degree Type

Dissertation

Date of Award

2016

Degree Name

Doctor of Philosophy

Department

Chemistry

Major

Organic Chemistry

First Advisor

Levi M. Stanley

Abstract

In this thesis, various palladium-catalyzed reactions to form C-N and C-C are discussed. These reactions span N-tert-prenylation, conjugate addition of arylboronic acids to β,β-disubstituted enones and Suzuki-Miyaura cross-coupling of haloarenes and arylboronic acids.

Palladium-catalyzed conjugate addition of wide range of arylboronic acids to β,β-disubstituted enones occur to form ketone products bearing benzylic all-carbon quaternary centers. A simple catalyst prepared from palladium trifluoroacetate and 2,2ʹ-bipyridine promotes these reactions. The use of aqueous sodium trifluoroacetate as the reaction medium significantly enhances reactivity and enables formation of challenging bis-benzylic and ortho-substituted benzylic all-carbon quaternary centers.

Palladium(II)-functionalized MOF-253 (MOF-253-Pd(OAc)2) can be used as a recyclable catalyst to form all-carbon quaternary centers via conjugate additions of arylboronic acids to β,β-disubstituted enones in aqueous media. MOF-253-Pd(OAc)2 can be reused 8 times to form ketone products in high yields and PXRD confirms the crystallinity remains intact. Additions of a range of stereoelectronically diverse arylboronic acids to a variety of β,β-disubstituted enones catalyzed by MOF-253-Pd(OAc)2 occur in modest-to-high yields.

The electronic and steric effects of linker substitution on the activity of metalated MOFs have been investigated in the context of Suzuki–Miyaura cross-coupling reactions. m-6,6´-Me2bpy-MOF-PdCl2 (UiO-67-Pd-6,6´-dimethyl-bpydc0.4/bpdc0.6) exhibited a remarkable enhancement in the activity compared to non-functionalized m-bpy-MOF-PdCl2 (UiO-67-Pd-bpydc0.5/bpdc0.5) and m-4,4´-Me2bpy-MOF-PdCl2(UiO-67-Pd-4,4´-dimethyl-bpydc0.4/bpdc0.6). This result clearly demonstrates that the stereoelectronic properties of metal-binding linker units are critical to the activity of single-site organometallic catalysts in MOFs.

Three distinct protocols are developed for the synthesis of N-tert-prenylindoles using indole, (η6-indole)Cr(CO)3, and indoline nucleophiles in the presence of the same catalyst generated from [Pd(η3-prenyl)Cl]2 and Xantphos. These reactions form N-tert-prenylindole products with a broad range of substitution and electronic character in high yields with high tert-prenyl-to-n-prenyl selectivity.

DOI

https://doi.org/10.31274/etd-180810-5457

Copyright Owner

Ryan Van Zeeland

Language

en

File Format

application/pdf

File Size

146 pages

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