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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

Silylketenes in the synthesis of heteroaromatics

Steer, James Timothy January 2001 (has links)
No description available.
2

Synthesis of a fluorous benzodithiol support and its utility in the construction of diverse ring systems

Sharma, Maya 10 September 2008 (has links)
A method for the synthesis of a symmetrical fluorous tagged benzodithiol support has been developed through a seven-step synthetic pathway. The Wittig olefination and catalytic hydrogenation reactions were employed to attach two perfluoroalkyl chains in the o-positions of phthalaldehyde. These fluorous tags were used as soluble supports which facilitated the purification of the crude reaction mixtures using fluorous solid phase extraction (FSPE). A selective and high yielding dibromination reaction was developed to synthesize a fluorous tagged 1,2-dibromo aryl compound. A thorough study was carried out to demonstrate the ease of an aryl-sulfur bond formation with the 1,2-dibromo compound varying palladium catalysts and ligands. A new palladium catalyzed dithiolation reaction is reported to synthesize a surrogated dithiol, which was exploited as a precursor for the synthesis of hitherto inaccessible symmetrical fluorous tagged benzodithiol support. The utility of the benzodithiol was explored by the synthesis of benzodithianes with two aldehydes. The lithiated dithiane generated was further used to form a C-C bond employing the umpolung reaction. The ring-closing metathesis reaction using Grubbs II catalyst was performed to construct 5-membered and 6-membered spiro-ring systems. Several approaches were made to form a C-C bond with lithiated dithianes using various nitrogen containing electrophiles leading to N-heterocycles. / October 2008
3

Synthesis of a fluorous benzodithiol support and its utility in the construction of diverse ring systems

Sharma, Maya 10 September 2008 (has links)
A method for the synthesis of a symmetrical fluorous tagged benzodithiol support has been developed through a seven-step synthetic pathway. The Wittig olefination and catalytic hydrogenation reactions were employed to attach two perfluoroalkyl chains in the o-positions of phthalaldehyde. These fluorous tags were used as soluble supports which facilitated the purification of the crude reaction mixtures using fluorous solid phase extraction (FSPE). A selective and high yielding dibromination reaction was developed to synthesize a fluorous tagged 1,2-dibromo aryl compound. A thorough study was carried out to demonstrate the ease of an aryl-sulfur bond formation with the 1,2-dibromo compound varying palladium catalysts and ligands. A new palladium catalyzed dithiolation reaction is reported to synthesize a surrogated dithiol, which was exploited as a precursor for the synthesis of hitherto inaccessible symmetrical fluorous tagged benzodithiol support. The utility of the benzodithiol was explored by the synthesis of benzodithianes with two aldehydes. The lithiated dithiane generated was further used to form a C-C bond employing the umpolung reaction. The ring-closing metathesis reaction using Grubbs II catalyst was performed to construct 5-membered and 6-membered spiro-ring systems. Several approaches were made to form a C-C bond with lithiated dithianes using various nitrogen containing electrophiles leading to N-heterocycles.
4

Synthesis of a fluorous benzodithiol support and its utility in the construction of diverse ring systems

Sharma, Maya 10 September 2008 (has links)
A method for the synthesis of a symmetrical fluorous tagged benzodithiol support has been developed through a seven-step synthetic pathway. The Wittig olefination and catalytic hydrogenation reactions were employed to attach two perfluoroalkyl chains in the o-positions of phthalaldehyde. These fluorous tags were used as soluble supports which facilitated the purification of the crude reaction mixtures using fluorous solid phase extraction (FSPE). A selective and high yielding dibromination reaction was developed to synthesize a fluorous tagged 1,2-dibromo aryl compound. A thorough study was carried out to demonstrate the ease of an aryl-sulfur bond formation with the 1,2-dibromo compound varying palladium catalysts and ligands. A new palladium catalyzed dithiolation reaction is reported to synthesize a surrogated dithiol, which was exploited as a precursor for the synthesis of hitherto inaccessible symmetrical fluorous tagged benzodithiol support. The utility of the benzodithiol was explored by the synthesis of benzodithianes with two aldehydes. The lithiated dithiane generated was further used to form a C-C bond employing the umpolung reaction. The ring-closing metathesis reaction using Grubbs II catalyst was performed to construct 5-membered and 6-membered spiro-ring systems. Several approaches were made to form a C-C bond with lithiated dithianes using various nitrogen containing electrophiles leading to N-heterocycles.

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