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M_Visco Dissertation.pdf (7.28 MB)

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Chiral Silanediols Designed for Enantioselective Heterocycle Functionalization

Visco, Michael David
http://orcid.org/0000-0002-0064-5605
http://rave.ohiolink.edu/etdc/view?acc_num=osu1492438099945523

Abstract Details

2017, Doctor of Philosophy, Ohio State University, Chemistry.
Molecular recognition by hydrogen-bond donors has proven to be applicable to various areas of research, including sensing and catalysis. (Thio)ureas have been established as the most conventional and widely studied hydrogen-bond donors, whereas other classes of hydrogen-bond donors, such as silanediols, are much less explored. Although silanediols have been studied in the context of self-recognition as well as, polymerization and materials chemistry, their exceptional hydrogen-bonding ability can also be exploited in catalysis. Prior to our group’s investigations, silanediols had not been demonstrated to participate in asymmetric hydrogen-bond donor catalysis, specifically anion-binding catalysis. Our laboratory was inspired by a report from the Kondo group demonstrating silanediols could recognize an array of anions, such as acetate, bromide and chloride, through hydrogen-bonding. Our curiosities prompted us to explore silanediol anion recognition in the context of asymmetric anion-binding catalysis by developing and synthesizing chiral, enantiopure silanediols. Limited information was available to aid us in the synthesis of chiral silanediols, as there were no reports of silanediols in the area of asymmetric catalysis prior to our research. Consequently, our group has dedicated great efforts to the synthesis and development of chiral silanediols to be utilized in anion-binding catalysis. We have successfully prepared a wide variety of chiral silanediols containing a diverse set of interesting scaffolds and studied their utility in enantioselective functionalization of heterocycles. Having several chiral silanediols on hand, we were eager to investigate their ability to participate in asymmetric anion-binding catalysis. Our initial investigations focused on the enantioselective functionalization of isoquinoline catalyzed by various BINOL-derived silanediols we developed and derivatized. We demonstrated that silanediols could affect the asymmetric addition of silyl ketene acetals to isoquinolinium ions in promising to high levels of enantiomeric excess. Through our investigations we collected valuable data on the physical properties of our silanediols, including pKa values and binding constants to give us insight to future catalyst designs. Most recently our group became interested in the chromanone class of natural products as they are known to exhibit powerful and fascinating biological activity. For example, gonytolide C is a known innate immune promoter and blennolide C exhibits antibacterial properties. Asymmetric intermolecular addition of carbonyl containing nucleophiles in the construction of chromanones had been elusive prior to our studies. We have established chiral silanediol catalysis as a viable method to afford these desired chromanone products through anion-binding catalysis with our developed VANOL- and BINOL-based catalysts. Our ultimate objective is to develop general strategies to construct the chromanone core and related heterocycles in a highly stereoselective manner via asymmetric anion-binding catalysis in the pursuit of these bioactive molecules. Through future collaborations, we hope to gather additional information and insight to the biological activities these interesting chromanone compounds exhibit.
Thomas Magliery (Advisor)
Anita Mattson (Committee Member)
Craig Forsyth (Committee Member)
David Nagib (Committee Member)
216 p.
Chemistry; Organic Chemistry
silanediols; benzylic silanes; organocatalysis; anion-binding catalysis; chromanone

Recommended Citations

Citations

  • Visco, M. D. (2017). Chiral Silanediols Designed for Enantioselective Heterocycle Functionalization [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492438099945523

    APA Style (7th edition)

  • Visco, Michael. Chiral Silanediols Designed for Enantioselective Heterocycle Functionalization. 2017. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1492438099945523.

    MLA Style (8th edition)

  • Visco, Michael. "Chiral Silanediols Designed for Enantioselective Heterocycle Functionalization." Doctoral dissertation, Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492438099945523

    Chicago Manual of Style (17th edition)

osu1492438099945523
211
© 2017, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.