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Timothy F. Jamison. Schleicher, Kristin D. (Kristin Diann) Massachusetts Institute of Technology. Dept. of Chemistry. Massachusetts Institute of Technology. Department of Chemistry 2011-04-04T21:21:07Z 2011-04-04T21:21:07Z 2010 2010 http://hdl.handle.net/1721.1/62138 709596374 Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2010. Vita. Cataloged from PDF version of thesis. Includes bibliographical references. Chapter I. In the presence of the N-heterocyclic carbene ligand IPr, the nickel(0)-catalyzed coupling reaction of a-olefins and branched aliphatic isocyanates provides c,-unsaturated amides arising from preferential C-C bond formation at the 2-position of the olefin. This sense of regioselectivity contrasts with the observed carboxamidation at the 1-position of the olefin when phosphine ligands are used. In this reaction, a simple alkene acts as the functional equivalent of a 2-alkenylmetal reagent. ... Chapter II. Synthetic studies on the antibiotic natural product ripostatin A have been carried out with the aim of constructing the C9-C1O bond via a nickel(0)-catalyzed coupling reaction of enynes and epoxides developed in our laboratory, followed by rearrangement of the resulting dienylcyclopropane intermediate to afford the skipped 1,4,7-triene. ... A cyclopropyl enyne fragment corresponding to C1-C9 of ripostatin A can be synthesized in high yield over 10 steps and was demonstrated to be a competent substrate for the nickel(0)-catalyzed coupling reaction with a model epoxide. The origin of regioselectivity in this particular transformation is also discussed. ... Several synthetic approaches towards the desired C1O-C26 epoxide fragment have been pursued. The presence of the C19-C20 trisubstituted olefin renders introduction of the epoxide via oxidation of or iodocyclization onto a terminal alkene unsuitable. Access of the epoxide by way of nucleophlic displacement should circumvent these problems. The C13 stereocenter can be set via the allylation and reductive decyanation of a cyanohydrin acetonide. ... A mild, fluoride-promoted decarboxylation enables the construction of the C15-C16 bond via an aldol reaction. This product of this transformation is of the correct oxidation state and three steps removed from the targeted epoxide fragment. by Kristin D. Schleicher. Ph.D. 254 p. eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Chemistry. Nickel-catalyzed preparation of acrylamides from alpha olefins and isocyanates ; Synthetic studies toward ripostatin A Synthetic studies toward ripostatin A Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="a7f6a589-9df1-4081-91eb-4cadb9dae9d2"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Nickel-catalyzed preparation of acrylamides from alpha olefins and isocyanates ; Synthetic studies toward ripostatin A</Title> <Subtitle>Synthetic studies toward ripostatin A</Subtitle> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2010</PublicationDate> <Authors> <Author> <DisplayName>Schleicher, Kristin D. (Kristin Diann)</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Chemistry.</Keyword> <Abstract>Chapter I. In the presence of the N-heterocyclic carbene ligand IPr, the nickel(0)-catalyzed coupling reaction of a-olefins and branched aliphatic isocyanates provides c,-unsaturated amides arising from preferential C-C bond formation at the 2-position of the olefin. This sense of regioselectivity contrasts with the observed carboxamidation at the 1-position of the olefin when phosphine ligands are used. In this reaction, a simple alkene acts as the functional equivalent of a 2-alkenylmetal reagent. ... Chapter II. Synthetic studies on the antibiotic natural product ripostatin A have been carried out with the aim of constructing the C9-C1O bond via a nickel(0)-catalyzed coupling reaction of enynes and epoxides developed in our laboratory, followed by rearrangement of the resulting dienylcyclopropane intermediate to afford the skipped 1,4,7-triene. ... A cyclopropyl enyne fragment corresponding to C1-C9 of ripostatin A can be synthesized in high yield over 10 steps and was demonstrated to be a competent substrate for the nickel(0)-catalyzed coupling reaction with a model epoxide. The origin of regioselectivity in this particular transformation is also discussed. ... Several synthetic approaches towards the desired C1O-C26 epoxide fragment have been pursued. The presence of the C19-C20 trisubstituted olefin renders introduction of the epoxide via oxidation of or iodocyclization onto a terminal alkene unsuitable. Access of the epoxide by way of nucleophlic displacement should circumvent these problems. The C13 stereocenter can be set via the allylation and reductive decyanation of a cyanohydrin acetonide. ... A mild, fluoride-promoted decarboxylation enables the construction of the C15-C16 bond via an aldol reaction. This product of this transformation is of the correct oxidation state and three steps removed from the targeted epoxide fragment.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>