Partial Isotopic Labeling Enables Direct (LC-)MS Analysis of Regioisomers and Insight on Kinetic Isotope Effects Christopher A Sojdak

Format:

Book

Thesis/Dissertation

Author/Creator:

Sojdak, Christopher A., author.

Contributor:

University of Pennsylvania. Chemistry., degree granting institution.

Language:

English

Subjects (All):

Organic chemistry.

Chemistry.

Physical chemistry.

0490.

0485.

0494.

Local Subjects:

Organic chemistry.

Chemistry.

Physical chemistry.

0490.

0485.

0494.

Physical Description:

1 electronic resource (590 pages)

Contained In:

Dissertations Abstracts International 86-12B

Place of Publication:

Ann Arbor : ProQuest Dissertations and Theses, 2025

Language Note:

English

Summary:

1.A method to cleave the C-C biaryl bond of binaphthyl derivatives under reductive conditions is described. Triflic acid employed together with a catalytic HAT reagent, 2-ethyl-9,10-dihydroxyanthracene, that is regenerated using H2 with catalytic Pd/C yielded monomeric products in improved yields. A range of substrates is disclosed, and kinetic analyses provide insight into the mechanism of aryl-aryl activation.2.C-H functionalization of complex substrates is highly enabling in total synthesis and in the development of late-stage drug candidates. Much work has been dedicated to developing new methods as well as predictive modeling to accelerate route scouting. However, workflows to identify regioisomeric products are arduous, typically requiring chromatographic separation and/or nuclear magnetic resonance spectroscopy analysis. In addition, most reports focus on major products or do not assign regioisomeric products which biases predictive models constructed from such data. Herein, we present a novel approach to complex reaction analysis utilizing partial deuterium labels which enables direct product identification via liquid chromatography-mass spectrometry. When combined with spectral deconvolution, the method generates product ratios while circumventing chromatography altogether. Competitive kinetic isotope effects can also be determined. The resultant data is expected to be useful in the construction of predictive models across several dimensions including reaction selectivity, the impact of structure on mechanism, mass spectral ionization patterns, and expedite the identification of drug metabolites.3.Volatile organic compounds (VOCs) are a class of compounds generated by both anthropogenic and biological processes, characterized by their high vapor pressure. Of the naturally produced VOCs alkenes such as isoprene and monoterpenes such as pinene, limonene, and myrcene are the largest components making up 69% and 10% respectively. In the troposphere these alkenes undergo ozonolysis eventually forming hydroxyl radicals via the carbonyl oxide intermediate called a Criegee intermediate. These hydroxyl radicals are a key oxidant in the upper atmosphere as they are responsible for reacting with a variety of greenhouse gases such as nitrous oxides, alkanes, carbon monoxide et cetera When reacting with alkanes via hydrogen-atom abstraction the resultant alkyl radicals can uptake oxygen leading to the formation of •QOOH species which further degrade to regenerate hydroxyl radicals. Understanding how these hydroxyl radicals are generated in the upper atmosphere allows for the generation of more robust complete climate models. In order to reliably generate reactive species in a laboratory setting a variety of iodinated alkanes/alkenes as well as alkyl peroxides are required. The synthesis of these materials as well as progress toward unpublished compounds is discussed herein

Notes:

Source: Dissertations Abstracts International, Volume: 86-12, Section: B.

Advisors: Kozlowski, Marisa C. Committee members: Goldberg, Karen I.; Walsh, Patrick J.; Winkler, Jeffrey D.

Ph.D. University of Pennsylvania 2025

Local Notes:

School code: 0175

ISBN:

9798280760288

Access Restriction:

Restricted for use by site license