Alexandria Digital Research Library

CuH-Catalyzed Reactions on Allylic Systems

Author:
Kahn, Dean Russell
Degree Grantor:
University of California, Santa Barbara. Chemistry and Biochemistry
Degree Supervisor:
Bruce H. Lipshutz
Place of Publication:
[Santa Barbara, Calif.]
Publisher:
University of California, Santa Barbara
Creation Date:
2015
Issued Date:
2015
Topics:
Organic chemistry and Chemistry
Keywords:
Methodology
Natural Products
Genres:
Dissertations, Academic and Online resources
Dissertation:
M.S.--University of California, Santa Barbara, 2015
Description:

The advent of copper hydride dates back over 150 years to 1844 when Wurtz reported its preparation via the reduction of copper oxide with hydrophosphoric acid, making copper hydride the oldest properly characterized metal hydride.

Chemists must often compromise a direct approach to building complex molecules due to the limited number of methods available to manipulate molecular functionality. While this methodology may be of greatest immediate use to organic chemists, the technology is potentially of use to chemists from a wide variety of disciplines. Materials chemists can take advantage of alkene functionality in polymerization reactions. Inorganic and physical chemists can study the mechanism of the organometallic catalyzed reaction. Chemical biologists and biochemists can more easily diversify chiral compound libraries in a drug discovery setting. Green and process chemists can continue to reduce the costs and environmental hazards of the technology while simultaneously moving to recyclable large-scale batches.

Although this chemistry methodology and synthetic analyses are quite technical, the implications of the research are of interest to popular non-scientific audiences. Molecular oxidants have been shown to damage cellular contents and promote ageing, thus antioxidants for the treatment of aging, such as CoQ10, or novel vitamin E analogues, are of importance to anyone interested in anti-aging medicines. As healthcare continues towards personalized, genetic based medicine, patients with GPX4 abnormalities that are unable to metabolize harmful molecular oxidants may find that a vitamin E analogue is the best molecule to mediate the effects of rapid aging caused by altered GPX4 expression.

Reductions of unsaturated systems with copper hydride have been well studied. However, the reactivity of copper hydride with allenes is an area that has yet to be fully explored. By placing an allene moiety next to an electron withdrawing aromatic or carbonyl species, it was discovered that a copper hydride catalyst is able to chemoselectively reduce the allene to an allyl species. When studying the reactivity of an enantioenriched propargyl carbonate with a chiral copper hydride catalyst, it was found that the starting material synthesized with S-BINOL saw >90% conversion with S-DTBM-Segphos CuH and only ∼50% conversion with R-DTBM-Segphos CuH, indicating a possible match-mismatch situation, which is in support of previously established mechanisms that indicate a backside S N2' delivery to propargyl systems. This methodology provides synthetic chemists a new retrosynthetic disconnection, as the propargyl carbonates can be readily synthesized from aldehydes and alkynyl nucleophiles. This novel transformation allows streamlined access to allylic aromatic compounds, which constitute a number of essential oil natural products, including elemicin, dillapiole, apiol, and myristicin.

Physical Description:
1 online resource (109 pages)
Format:
Text
Collection(s):
UCSB electronic theses and dissertations
ARK:
ark:/48907/f3qz284t
ISBN:
9781339084329
Catalog System Number:
990045715760203776
Rights:
Inc.icon only.dark In Copyright
Copyright Holder:
Dean Kahn
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