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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 in Acceptor-Acceptor-Donor Cyclopropanes

Reyes, Yahaira De Bary 13 December 2014 (has links)
Isolated from Spongosorites sp., Dragmacidin E is of synthetic interest due to its biological properties and novel molecular structure. A promising therapeutic target, its synthetic challenge is attributed to its heptacyclic core. In this study, we propose the synthesis of a Dragmacidin E heptacyclic core precursor, mediated through a Lewis acid (LA) mediated cyclization of an acceptoreptor-donor (AAD) cyclopropane. Utilizing a model study, alkoxy AAD cyclopropanes were investigated to develop a protocol for precursor synthesis. After generating various ethyl-α-diazobenzoyl acetate derivatives, the metal catalyzed cyclopropanation reaction of these compounds was studied. With vinyl acetate and Rh2esp2, acetoxy AAD cyclopropanes were synthesized in yields ranging from 12 % - 53 %. These cyclopropanes were successfully generated and rearrangement into dihydrofuran products was avoided. To complete our model study, LA cyclization of acetoxy AAD cyclopropanes was studied. Using stoichiometric quantities of TiCl4<.sub>, naphthol derivatives were synthesized in one step.

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