Studies Toward The Enantioselective Total Synthesis Of The Martinella Alkaloids

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Studies Toward The Enantioselective Total Synthesis Of The Martinella Alkaloids

Show simple item record Badarinarayana, Vivek en_US 2007-08-23T01:56:42Z 2007-08-23T01:56:42Z 2007-08-23T01:56:42Z June 2006 en_US
dc.identifier.other DISS-1366 en_US
dc.description.abstract This dissertation consists of two parts. The first part describes the enantioselective total synthesis of martinellic acid. The Martinella alkaloids have attracted considerable attention in the synthetic community over the past few years. This interest is due in large part to their unique structure and useful biological activity (bradykinin receptor antagonist). In model systems we have successfully used the [3+2] azomethine ylide-alkene cycloaddition to construct the heterocyclic core of these alkaloids. The enantioselective approach described herein also involves the azomethine ylide-alkene cycloaddition as a key step in the total synthesis. The pyrrolo[3,2-c]quinoline core of this alkaloid was constructed in an enantioselective fashion by the elaboration of an N-aryl pyrrolidinone, which was obtained via Pd-catalyzed aryl amination reaction using a non-racemic lactam. Pirkle's chiral solvating agent was successfully used to demonstrate the stereochemical integrity of not only the N-aryl lactam (obtained by Pd-catalyzed cross-coupling) but also the cycloaddition precursor and the cycloaddition product (tetracyclic pyrroloquinoline core). The tetracyclic compound obtained via the azomethine ylide-alkene cycloaddition was elaborated to (-)-martinellic acid in 11 steps and 6% overall yield. The second part of this dissertation describes application of several novel organometallic complexes for carrying out various organic transformations. A fluorinated tris(pyrazolyl)borato silver(I) complex catalyzes the addition of ethyl diazoacetate to benzene rings, providing norcaradienes, which undergo electrocyclization to provide the corresponding cycloheptatriene (the Bűchner reaction). These reactions are surprisingly selective for addition to the aromatic moiety rather than C-H insertion. A copper complex containing a fluorinated triazapentadienyl ligand has been used to catalyze some carbene and nitrene addition and insertion chemistry. Nitrene addition occurs rapidly and with both aryl and alkyl substituted olefins providing the corresponding aziridine. The carbene transfer reactions that were attempted include C-H insertion, O-H insertion and N-H insertion, of which the latter two were very efficient. en_US
dc.description.sponsorship Lovely, Carl en_US
dc.language.iso EN en_US
dc.publisher Chemistry & Biochemistry en_US
dc.title Studies Toward The Enantioselective Total Synthesis Of The Martinella Alkaloids en_US
dc.type Ph.D. en_US
dc.contributor.committeeChair Lovely, Carl en_US Chemistry & Biochemistry en_US Chemistry & Biochemistry en_US University of Texas at Arlington en_US doctoral en_US Ph.D. en_US
dc.identifier.externalLinkDescription Link to Research Profiles

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