4-membered ring construction in the synthesis of natural products : total synthesis of Ladderane phospholipids and progress toward the synthesis of fomannosin

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Chapter 1 introduces anaerobic ammonium oxidizing (anammox) bacteria and the ladderane lipids, unusual membrane lipids consisting of linearly concatenated cyclobutane motifs. The distinctive biological features and global applications of anammox bacteria are covered, with a focus on anammox catabolism and the possible function of ladderane lipids. The isolation and structural determination of ladderane lipids are outlined, as well as previous and concurrent synthetic efforts. Chapter 2 details our extensive synthetic efforts toward the synthesis of ladderane lipids. Key features of our synthesis of a [5]-ladderane include a scalable synthesis of key building block bicyclo[2.2.0]hex-2-ene, copper(I)-mediated dimerization of this building block, and C--H functionalization of the ladderane core. We also present a synthesis of [3]-ladderane utilizing a [2+2] photocycloaddition with a chiral dihalide, stereospecific alkylzinc addition, and unusual bis-hydrazone oxidative decomposition. Our efforts to determine for the first time the absolute stereochemical configuration of ladderane lipids are also detailed. Finally, the synthesis of two natural and one unnatural ladderane phospholipid as well as biophysical interrogation of synthetic ladderane phospholipids is presented. Chapter 3 describes an ongoing synthetic campaign toward the phytotoxic sesquiterpene fomannosin. Our synthesis requires a challenging quaternary carbon-forming epoxide opening reaction, as well as a cascade cyclization-Ramberg--Bäcklund ring contraction sequence. Efforts toward the completion of the natural product are presented.


Type of resource text
Form electronic resource; remote; computer; online resource
Extent 1 online resource.
Place California
Place [Stanford, California]
Publisher [Stanford University]
Copyright date 2019; ©2019
Publication date 2019; 2019
Issuance monographic
Language English


Author Cohen, Carolyn Michelle
Degree supervisor Burns, Noah
Thesis advisor Burns, Noah
Thesis advisor Bertozzi, Carolyn R, 1966-
Thesis advisor Du Bois, Justin
Degree committee member Bertozzi, Carolyn R, 1966-
Degree committee member Du Bois, Justin
Associated with Stanford University, Department of Chemistry.


Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Carolyn Michelle Cohen.
Note Submitted to the Department of Chemistry.
Thesis Thesis Ph.D. Stanford University 2019.
Location electronic resource

Access conditions

© 2019 by Carolyn Michelle Cohen
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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