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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

Part A: Progress Towards the Total Synthesis of (±)-Communesin F; Part B: Aluminum as a Catalyst for the Diels-Alder Cycloaddition of Highly Hindered Dienophiles.

Newbury, Daniel John 15 March 2013 (has links)
This is a thesis in two parts. Part A examines two potential routes towards the synthesis of the communesin family of alkaloids, as well as an overview of some of the successful synthetic routes to date. Our first proposed route involves the gold catalyzed isomerization of an o-amino aryallene to a vinyl imine and subsequent (formal) cycloaddition with an indole. This would have allowed quick access to the pentacyclic core of the communesins; however, the unexpected 5-endo-dig product was exclusively obtained in good to excellent yields. The second route involves the use of a Meerwein- Eschenmoser Claisen rearrangement. This route was successful in affording the C, D, E and F rings of the communesin alkaloids, however future work is required for completion of the synthesis. Also discussed in these sections is an alternative endgame approach involving a novel Pictet-Spangler reaction to afford the G ring, and the possibility of an asymmetric variation to the proposed route. Part B examines the use of alkyl aluminum sesquichlorides in the catalysis of Diels-Alder cycloadditions of sterically hindered systems, a current obstacle in organic chemistry. Previously developed methods are discussed and preliminary results are presented. Ethyl aluminum sesquichloride is compared to other alkyl aluminum catalyst, and the effects of temperature, catalysts loading, choice of solvent, the use of additives, and the use of chiral oxazolidinones are reported and what these result can tell us about the mechanism of catalysis are discussed.
2

Part A: Progress Towards the Total Synthesis of (±)-Communesin F; Part B: Aluminum as a Catalyst for the Diels-Alder Cycloaddition of Highly Hindered Dienophiles.

Newbury, Daniel John 15 March 2013 (has links)
This is a thesis in two parts. Part A examines two potential routes towards the synthesis of the communesin family of alkaloids, as well as an overview of some of the successful synthetic routes to date. Our first proposed route involves the gold catalyzed isomerization of an o-amino aryallene to a vinyl imine and subsequent (formal) cycloaddition with an indole. This would have allowed quick access to the pentacyclic core of the communesins; however, the unexpected 5-endo-dig product was exclusively obtained in good to excellent yields. The second route involves the use of a Meerwein- Eschenmoser Claisen rearrangement. This route was successful in affording the C, D, E and F rings of the communesin alkaloids, however future work is required for completion of the synthesis. Also discussed in these sections is an alternative endgame approach involving a novel Pictet-Spangler reaction to afford the G ring, and the possibility of an asymmetric variation to the proposed route. Part B examines the use of alkyl aluminum sesquichlorides in the catalysis of Diels-Alder cycloadditions of sterically hindered systems, a current obstacle in organic chemistry. Previously developed methods are discussed and preliminary results are presented. Ethyl aluminum sesquichloride is compared to other alkyl aluminum catalyst, and the effects of temperature, catalysts loading, choice of solvent, the use of additives, and the use of chiral oxazolidinones are reported and what these result can tell us about the mechanism of catalysis are discussed.
3

Part A: Progress Towards the Total Synthesis of (±)-Communesin F; Part B: Aluminum as a Catalyst for the Diels-Alder Cycloaddition of Highly Hindered Dienophiles.

Newbury, Daniel John January 2013 (has links)
This is a thesis in two parts. Part A examines two potential routes towards the synthesis of the communesin family of alkaloids, as well as an overview of some of the successful synthetic routes to date. Our first proposed route involves the gold catalyzed isomerization of an o-amino aryallene to a vinyl imine and subsequent (formal) cycloaddition with an indole. This would have allowed quick access to the pentacyclic core of the communesins; however, the unexpected 5-endo-dig product was exclusively obtained in good to excellent yields. The second route involves the use of a Meerwein- Eschenmoser Claisen rearrangement. This route was successful in affording the C, D, E and F rings of the communesin alkaloids, however future work is required for completion of the synthesis. Also discussed in these sections is an alternative endgame approach involving a novel Pictet-Spangler reaction to afford the G ring, and the possibility of an asymmetric variation to the proposed route. Part B examines the use of alkyl aluminum sesquichlorides in the catalysis of Diels-Alder cycloadditions of sterically hindered systems, a current obstacle in organic chemistry. Previously developed methods are discussed and preliminary results are presented. Ethyl aluminum sesquichloride is compared to other alkyl aluminum catalyst, and the effects of temperature, catalysts loading, choice of solvent, the use of additives, and the use of chiral oxazolidinones are reported and what these result can tell us about the mechanism of catalysis are discussed.

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