New Methods for the α-Functionalization of Thioesters and Activated Hydrazones and an Application Toward the Total Synthesis of Apratoxin D

<p>Cascade reactions, also referred to as domino reactions, have been widely used for the formation of carbon-carbon bonds. This type of reaction has the potential to circumvent protection and deprotection steps, shortening an overall synthetic process.</p><p>The Morita-Baylis-Hill...

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Main Author:	Tarsis, Emily Michelle
Other Authors:	Coltart, Don M
Published:	2010
Subjects:	Organic Chemistry
Online Access:	http://hdl.handle.net/10161/3074

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spelling	ndltd-DUKE-oai-dukespace.lib.duke.edu-10161-30742013-01-07T20:07:39ZNew Methods for the α-Functionalization of Thioesters and Activated Hydrazones and an Application Toward the Total Synthesis of Apratoxin DTarsis, Emily MichelleOrganic Chemistry<p>Cascade reactions, also referred to as domino reactions, have been widely used for the formation of carbon-carbon bonds. This type of reaction has the potential to circumvent protection and deprotection steps, shortening an overall synthetic process.</p><p>The Morita-Baylis-Hillman (MBH) reaction is a particularly notable example of an anionic domino reaction which provides straightforward access to β'-hydroxy-α,β-unsaturated carbonyl compounds from aldehydes and α,β-unsaturated carbonyls. However, despite the importance of the Baylis-Hillman reaction, it is slow, reaction yields are quite low, and the process is not general, as it rarely works for β-substituted α,β-unsaturated carbonyl species. Herein, we report an alternative approach to the preparation of MBH adducts employing an anti-selective direct aldol cascade reaction followed by oxidative elimination. This alternative process is rapid, efficient, and generally applicable, even to β-substituted α,β-unsaturated compounds. </p><p>Progress toward the asymmetric total synthesis of apratoxin D is described. The key step of the synthesis is the asymmetric α,α-bisalkylation of chiral N-amino cyclic carbamate (ACC) hydrazones, a new methodology developed by our group. Herein we demonstrate the utility of this method for convergent total syntheses.</p>DissertationColtart, Don M2010Dissertationhttp://hdl.handle.net/10161/3074
collection	NDLTD
sources	NDLTD
topic	Organic Chemistry
spellingShingle	Organic Chemistry Tarsis, Emily Michelle New Methods for the α-Functionalization of Thioesters and Activated Hydrazones and an Application Toward the Total Synthesis of Apratoxin D
description	<p>Cascade reactions, also referred to as domino reactions, have been widely used for the formation of carbon-carbon bonds. This type of reaction has the potential to circumvent protection and deprotection steps, shortening an overall synthetic process.</p><p>The Morita-Baylis-Hillman (MBH) reaction is a particularly notable example of an anionic domino reaction which provides straightforward access to β'-hydroxy-α,β-unsaturated carbonyl compounds from aldehydes and α,β-unsaturated carbonyls. However, despite the importance of the Baylis-Hillman reaction, it is slow, reaction yields are quite low, and the process is not general, as it rarely works for β-substituted α,β-unsaturated carbonyl species. Herein, we report an alternative approach to the preparation of MBH adducts employing an anti-selective direct aldol cascade reaction followed by oxidative elimination. This alternative process is rapid, efficient, and generally applicable, even to β-substituted α,β-unsaturated compounds. </p><p>Progress toward the asymmetric total synthesis of apratoxin D is described. The key step of the synthesis is the asymmetric α,α-bisalkylation of chiral N-amino cyclic carbamate (ACC) hydrazones, a new methodology developed by our group. Herein we demonstrate the utility of this method for convergent total syntheses.</p> === Dissertation
author2	Coltart, Don M
author_facet	Coltart, Don M Tarsis, Emily Michelle
author	Tarsis, Emily Michelle
author_sort	Tarsis, Emily Michelle
title	New Methods for the α-Functionalization of Thioesters and Activated Hydrazones and an Application Toward the Total Synthesis of Apratoxin D
title_short	New Methods for the α-Functionalization of Thioesters and Activated Hydrazones and an Application Toward the Total Synthesis of Apratoxin D
title_full	New Methods for the α-Functionalization of Thioesters and Activated Hydrazones and an Application Toward the Total Synthesis of Apratoxin D
title_fullStr	New Methods for the α-Functionalization of Thioesters and Activated Hydrazones and an Application Toward the Total Synthesis of Apratoxin D
title_full_unstemmed	New Methods for the α-Functionalization of Thioesters and Activated Hydrazones and an Application Toward the Total Synthesis of Apratoxin D
title_sort	new methods for the α-functionalization of thioesters and activated hydrazones and an application toward the total synthesis of apratoxin d
publishDate	2010
url	http://hdl.handle.net/10161/3074
work_keys_str_mv	AT tarsisemilymichelle newmethodsforthe945functionalizationofthioestersandactivatedhydrazonesandanapplicationtowardthetotalsynthesisofapratoxind
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New Methods for the &#945;-Functionalization of Thioesters and Activated Hydrazones and an Application Toward the Total Synthesis of Apratoxin D

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New Methods for the α-Functionalization of Thioesters and Activated Hydrazones and an Application Toward the Total Synthesis of Apratoxin D