| NSF Org: |
CHE Division Of Chemistry |
| Recipient: |
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| Initial Amendment Date: | June 23, 2017 |
| Latest Amendment Date: | June 23, 2017 |
| Award Number: | 1665113 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Tingyu Li
tli@nsf.gov (703)292-4949 CHE Division Of Chemistry MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | July 1, 2017 |
| End Date: | June 30, 2021 (Estimated) |
| Total Intended Award Amount: | $420,000.00 |
| Total Awarded Amount to Date: | $420,000.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
85 S PROSPECT STREET BURLINGTON VT US 05405-1704 (802)656-3660 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
85 So. Prospect St. Burlington VT US 05405-0160 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | CMFP-Chem Mech Funct, and Prop |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.049 |
ABSTRACT
In this project funded by the Chemical Structure, Dynamic & Mechanism B Program of the Chemistry Division, Professor Matthias Brewer of the Department of Chemistry at the University of Vermont is studying the reactivity of vinyl cations. The goal of this research is to better understand the reactivity of these high-energy intermediates and to develop new carbon-carbon bond forming reactions. This work takes advantage of the fact that vinyl cations can react through unique and poorly understood mechanistic pathways that have not been fully exploited in synthesis. In addition to providing a better understanding of the inherent reactivity of vinyl cations, this work provides several useful complexity-building ring-forming reactions that could enable the synthesis of structurally complex bicyclic and polycyclic products and more basic molecular scaffolds that serve as useful synthetic intermediates. The graduate and undergraduate students and economically disadvantaged high school students (via the ACS Project SEED program) who work on this project receive excellent training in organic chemistry and learn to conduct mechanistic studies, reaction optimization and development studies, and become adept at compound characterization and structure elucidation. In addition, the PI is looking for innovative ways to promote undergraduate research opportunities and study abroad opportunities for undergraduate Chemistry and Biochemistry majors.
While trisubstituted cations (i.e. carbenium ions) are one of the best studied and most important classes of intermediates in organic chemistry, disubstituted cations (i.e. vinyl cations) have not received the same level of attention from the synthetic community. This proposal seeks to better understand the intrinsic reactivity of vinyl cations and the mechanisms through which vinyl cations react. Specifically, this work: 1) Explores the reactivity of vinyl cations in internal redox reactions that result in C-C bond formation by remote C-H functionalization; 2) Provides a better understanding of the insertion process through mechanistic studies; 3) Defines the migratory aptitude of groups in 1,2-shifts across the alkene of vinyl cations; 4) Studies C-C bond formation by reaction of vinyl cations with remote pi-systems. These studies could provide new and unique ways to prepare simple structures that will be valuable synthetic intermediates, as well as important carbocyclic scaffolds that would be difficult to prepare by traditional means.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Award 1665113 supported the research of six Ph.D. students, two undergraduate students, and one ACS Project SEED student. The ACS Project SEED program supports economically disadvantaged high school students by providing them with a summer research opportunity in the hopes that these students will continue on to study a STEM related field at the University level. The student that worked on this project is now a Chemistry major at UVM. Each of these students developed skills related to the practical techniques required for synthetic organic chemistry research as well a training on synthetic methods development and mechanistic investigations. In addition, these students honed their presentation skills and gained a broader range of organic chemistry knowledge through group meetings that involved literature presentations and problem sets. Four of the Ph.D. students completed their dissertations while working on this award and continued on to postdoctoral studies or teaching positions.
The research undertaken with this funding was related to synthetic organic chemistry. More specifically, the work focused on studying the reactivity of vinyl cations in intramolecular processes. The research conducted under this award is important because it takes advantage of the unique reactivity displayed by vinyl cations to give new ways to prepare simple structures that are valuable synthetic intermediates, as well as important carbocyclic scaffolds that are difficult to prepare by traditional means. This research helps to better define the reactivity of this important but overlooked class of cations, provides synthetic chemists with new insight into the reactivity of these high energy species, and establishes new methods to prepare fundamentally important molecular scaffolds. Over the course of this work, we discovered that one of the vinyl cation precursors (a vinyl diazonium ion) could act as a reactive intermediate to form a new carbon-carbon bond. This discovery is important because no general and useful synthetic transformations have been developed that take advantage of vinyl diazonium ions other than their use as vinyl cation precursors. The products formed from this reaction have new tertiary or quaternary centers, and it is significant that the diazo functional group is retained within the product for future manipulation.
Last Modified: 09/14/2021
Modified by: Matthias Brewer
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