David Walton
Postdoctoral Research Fellow, Chemistry
Professional Education
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Bachelor of Science, Millersville Univ Of Pennsylvania (2018)
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Doctor of Philosophy, California Institute of Technology (2019)
All Publications
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A General Strategy for Visible-Light Decaging Based on the Quinone Trimethyl Lock
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
2017; 139 (13): 4655–58
Abstract
Visible-light triggered quinone trimethyl locks are reported as a general design for long-wavelength photoremovable protecting groups for alcohols and amines. Intramolecular photoreduction unmasks a reactive phenol that undergoes fast lactonization to release alcohols and amines. Model substrates are released in quantitative yield along with well-defined, colorless hydroquinone byproducts. Substituent modifications of the quinone core allow absorption from 400 to 600 nm.
View details for DOI 10.1021/jacs.7b01548
View details for Web of Science ID 000398764000013
View details for PubMedID 28324654
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Mechanistic Studies of the Photoinduced Quinone Trimethyl Lock Decaging Process
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
2017; 139 (13): 4729–36
Abstract
Mechanistic studies of a general reaction that decages a wide range of substrates on exposure to visible light are described. The reaction involves a photochemically initiated reduction of a quinone mediated by an appended thioether. After reduction, a trimethyl lock system incorporated into the quinone leads to thermal decaging. The reaction could be viewed as an electron-transfer initiated reduction of the quinone or as a hydrogen abstraction-Norrish Type II-reaction. Product analysis, kinetic isotope effects, stereochemical labeling, radical clock, and transient absorption studies support the electron transfer mechanism. The differing reactivities of the singlet and triplet states are determined, and the ways in which this process deviates from typical quinone photochemistry are discussed. The mechanism suggests strategies for extending the reaction to longer wavelengths that would be of interest for applications in chemical biology and in a therapeutic setting.
View details for DOI 10.1021/jacs.6b12007
View details for Web of Science ID 000398764000024
View details for PubMedID 28199106