Chemical processes that enable fragment union between functionalized coupling partners define a subset of reactions that are exceptionally powerful. While they can help to define efficient pathways to complex molecules, they are also of central importance to medicinal chemistry. Despite the importance of such reactions in chemical synthesis, it is surprising that only a handful of robust pathways are available for arguably the most relevant of such processes in natural product synthesis: intermolecular C-C bond formation between highly functionalized coupling partners. This research program is focused on establishing a new approach to stereoselective chemical synthesis that derives from design, discovery and development of new intermolecular C-C bond-forming reactions that proceed by metallacyclic intermediates, and establishing their utility in natural product synthesis Our initial phases of this program were heavily focused on methods development with recent efforts beginning to encompass the application of some of our coupling chemistry in natural product synthesis. Such latter study is critical for the evolution of new synthetic methods and the demonstration that they have a substantial impact on strategy and efficiency in a variety of target-oriented settings. To date, our efforts have established a foundation of new coupling technology that addresses structural motifs resident in a great variety of natural product targets (alkaloids, terpenes, and fatty acids), often doing so with exquisite levels of chemo-, regio-, and stereoselectivity. As our program moves forward, we are committed to: (1) confirming the utility of metallacycle-mediated cross-coupling technology in complex molecule synthesis, (2) the establishment of new retrosynthetic strategies in target-oriented synthesis that emerge from our chemical methods, and (3) the first, or the most concise, syntheses of a range of natural products. In this way, our proposed studies will advance new modes of chemical reactivity to firmly establish a foundation of reaction methodology that has the potential to have a profound impact on target-oriented synthesis (at the strategic level). As such, continued development of this program promises the delivery of science that will have a significant impact on mankind's search for medicinally relevant small molecules and will enable scientific discovery at the interface of chemistry with biology and medicine.

Public Health Relevance

The manner in which complex molecules are synthesized defines the role that organic chemistry plays in biology and medicine - a relationship that derives from the impact that chemical synthesis has on the availability of unique small molecules with medicinally relevant profiles. Chemical reactions that enable convergent coupling of complex partners are of central significance to organic synthesis, as they provide a means to both enhance efficiency in routes to intricate targets, and define workable schemes to establish SAR in medicinal chemistry. Our scientific pursuits are aimed at addressing the hypothesis that recently discovered fragment coupling reactions will have a profound and beneficial impact on the efficiency with which complex molecules are prepared - as evidenced by demonstrations in the context of rare natural products known to possess a range of medicinally relevant properties (i.e. anticancer, antifungal, analgesic and antibiotic).

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM080266-13
Application #
9265869
Study Section
Synthetic and Biological Chemistry B Study Section (SBCB)
Program Officer
Lees, Robert G
Project Start
2007-03-12
Project End
2020-04-30
Budget Start
2017-05-01
Budget End
2018-04-30
Support Year
13
Fiscal Year
2017
Total Cost
Indirect Cost
Name
Dartmouth College
Department
Chemistry
Type
Graduate Schools
DUNS #
041027822
City
Hanover
State
NH
Country
United States
Zip Code
03755
Kim, Wan Shin; Du, Kang; Eastman, Alan et al. (2018) Synthetic nat- or ent-steroids in as few as five chemical steps from epichlorohydrin. Nat Chem 10:70-77
Micalizio, Glenn C; Mizoguchi, Haruki (2017) The Development of Alkoxide-Directed Metallacycle-Mediated Annulative Cross-Coupling Chemistry. Isr J Chem 57:228-238
Kier, Matthew J; Leon, Robert M; O'Rourke, Natasha F et al. (2017) Synthesis of Highly Oxygenated Carbocycles by Stereoselective Coupling of Alkynes to 1,3- and 1,4-Dicarbonyl Systems. J Am Chem Soc 139:12374-12377
O'Rourke, Natasha F; A, Mu; Higgs, Henry N et al. (2017) Function-Oriented Studies Targeting Pectenotoxin 2: Synthesis of the GH-Ring System and a Structurally Simplified Macrolactone. Org Lett 19:5154-5157
Mizoguchi, Haruki; Micalizio, Glenn C (2016) Synthesis of Angularly Substituted trans-Fused Decalins through a Metallacycle-Mediated Annulative Cross-Coupling Cascade. Angew Chem Int Ed Engl 55:13099-13103
O'Rourke, Natasha F; Micalizio, Glenn C (2016) Cyclopropenes in Metallacycle-Mediated Cross-Coupling with Alkynes: Convergent Synthesis of Highly Substituted Vinylcyclopropanes. Org Lett 18:1250-3
Cheng, Xiayun; Micalizio, Glenn C (2016) Synthesis of Neurotrophic Seco-prezizaane Sesquiterpenes (1R,10S)-2-Oxo-3,4-dehydroneomajucin, (2S)-Hydroxy-3,4-dehydroneomajucin, and (-)-Jiadifenin. J Am Chem Soc 138:1150-3
O'Rourke, Natasha F; Kier, Matthew J; Micalizio, Glenn C (2016) Metallacycle-Mediated Cross-Coupling in Natural Product Synthesis. Tetrahedron 72:7093-7123
Aquino, Claudio; Greszler, Stephen N; Micalizio, Glenn C (2016) Synthesis of the Cortistatin Pentacyclic Core by Alkoxide-Directed Metallacycle-Mediated Annulative Cross-Coupling. Org Lett 18:2624-7
Cassidy, James S; Mizoguchi, Haruki; Micalizio, Glenn C (2016) Acceleration of metallacycle-mediated alkyne-alkyne cross-coupling with TMSCl. Tetrahedron Lett 57:3848-3850

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