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Part I. Studies on the use of bidentate ligands in the directed Pauson-Khand reaction. Part II. The Pauson-Khand reaction in synthesis: Towards the total synthesis of asteriscanolide

Two main investigations based on the Pauson-Khand reaction were performed. / The use of bidentate ligands in the directed Pauson-Khand reaction was investigated. Substrates with a three-carbon linkage between the two heteroatoms gave better results than substrates containing two-carbon tethers. Higher yields and better regioselectivities were observed with thioamines and bisthioethers compared to diamines. Overall, only a few bidentate substrates showed marked improvements over previous results obtained with analogous monodentate compounds. Rationalizations based on the possible modes of cycloaddition operative for the various substrates studied are presented. / Investigations were performed on two main approaches towards the total synthesis of Asteriscanolide, both of which employ the Pauson-Khand reaction at a crucial juncture. Studies towards the preparation of the bridged bicyclic intermediate needed for the key cycloaddition reaction in the first strategy were not encouraging. Intermolecular Pauson-Khand reactions of alkynoate complexes were studied towards developing a useful methodology for use within the second synthetic scheme. The amine oxide-promoted reaction between propene and (ethyl 5- (t-butyldimethylsilyl) oxy)-2-pentynoate)dicobalthexacarbonyl gave the desired cyclopentenones in $>$30:1 ratio and 90% yield. Succeeding steps were performed in excellent yield. Attempts to reduce the double bond in a number of intermediates are described. / Source: Dissertation Abstracts International, Volume: 55-04, Section: B, page: 1438. / Major Professor: Marie E. Krafft. / Thesis (Ph.D.)--The Florida State University, 1994.

Identiferoai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77164
ContributorsJuliano, Carmelinda Alvarez., Florida State University
Source SetsFlorida State University
LanguageEnglish
Detected LanguageEnglish
TypeText
Format443 p.
RightsOn campus use only.
RelationDissertation Abstracts International

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