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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Studies on the total synthesis of (±)-rocaglamide

Freund, Wesley Allen 2009 August 1900 (has links)
The use of a Nazarov cyclization for the diastereoselective synthesis of rocaglamide was studied. Chapter 1 discusses the biological activity of the rocaglamide family of natural products and details the previous synthetic work on these compounds. Chapter 2 discusses the approaches taken in the Magnus group for the total synthesis of rocaglamide. Several approaches to the natural product were undertaken. Using a novel acid bromide induced Nazarov cyclization, construction of the C-ring of the natural product was achieved. Attempts to construct the remainder of rocaglamide were ultimately unsuccessful. / text
2

Ring-opening benzannulations of cyclopropenes, alkylidene cyclopropanes, and 2,3-dihydrofuran acetals: A complementary approach to benzo-fused (hetero)aromatics

Aponte-Guzman, Joel 27 May 2016 (has links)
Over the past decades, functional group manipulation of aromatic precursors has been a common strategy to access new aromatic compounds. However, these classical methods, such as Friedel-Crafts alkylations and electrophilic/nucleophilic aromatic substitutions, have shown lack of regioselectivity besides the use of activators in excess amounts. To this end, numerous benzannulations to form benzo-fused substrates via Diels-Alder (DA), ring-closing metathesis (RCM), cycloaddition, and transition-metal-promoted processes have been reported. Appending a benzene ring directly onto a pre-existing ring is preferable to many classical methods due to the likely reduction of reaction steps and superior regiocontrol. However, many of these benzannulation reactions require air- and/or moisture- sensitive reaction conditions, a last oxidation step, or the use of highly functionalized precursors. Here we disclose three ‘complementary’ intramolecular ring-opening benzannulations to access a large array of functionalized (hetero)aromatic scaffolds utilizing cyclopropenes-3,3-dicarbonyls, alkylidene cyclopropanes-1,1-diesters, and 2,3-dihydrofuran O,O- and N,O- acetals as building blocks. More than 70 benzo-fused aromatic compounds were synthesized using this complementary approach with yields up to 98% and low catalyst loadings. With these benzannulation reactions in hand, we aim to open the synthetic door to a handful of bioactive natural products.

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