Olefin Cyclopropanation Catalyzed by Iridium(III) Porphyrin Complexes

dc.contributor.author Anding, Bernie
dc.contributor.author Ellern, Arkady
dc.contributor.author Woo, L.
dc.contributor.author Woo, L. Keith
dc.contributor.department Chemistry
dc.date 2018-02-17T09:26:47.000
dc.date.accessioned 2020-06-30T01:22:48Z
dc.date.available 2020-06-30T01:22:48Z
dc.date.copyright Sun Jan 01 00:00:00 UTC 2012
dc.date.issued 2012-04-01
dc.description.abstract <p>Tetratolylporphyrinato (TTP) iridium complexes were shown to be extremely active and robust catalysts for the cyclopropanation of olefins using diazo compounds as carbene sources. Ir(TTP)CH3 (<strong>1</strong>) catalyzed the cyclopropanation of styrene with ethyl diazoacetate (EDA) at −78 °C and achieved 4.8 × 105 turnovers in three successive reagent additions with no sign of deactivation. High yields and moderate trans selectivities were attained for electron-rich and sterically unhindered substrates. A Hammett ρ+ value of −0.23 was determined by competition experiments with para-substituted styrenes. Furthermore, competitive cyclopropanation of styrene and styrene-<em>d</em>8 with EDA and <strong>1</strong> demonstrated a moderate inverse secondary isotope effect of 0.86 ± 0.03. These data are consistent with a catalytic cycle that proceeds through a metalloporphyrin carbene intermediate. Carbene transfer to olefin substrates appears to be rate limiting, as indicated by kinetic studies. Hexavalent iridium halogenato tetratolylporphyrinato complexes of the form Ir(TTP)X(L), where X = Cl, Br, I, NCS and L = CO, NMe3 (<strong>2</strong>–<strong>6</strong>), and cationic analogues, where X = BF4 and L = CO or vacant site (<strong>7</strong>, <strong>8</strong>), also demonstrated high catalytic cyclopropanation activity.</p>
dc.description.comments <p>Reprinted (adapted) with permission from <em>Organometallics</em> 31 (2012): 3628, doi:<a href="http://dx.doi.org/10.1021/om300135f" target="_blank">10.1021/om300135f</a>. Copyright 2012 American Chemical Society.</p>
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dc.identifier archive/lib.dr.iastate.edu/chem_pubs/777/
dc.identifier.articleid 1802
dc.identifier.contextkey 7966092
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath chem_pubs/777
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/15267
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/chem_pubs/777/0-L_2012_Woo_OlefinCyclopropanation.pdf|||Sat Jan 15 01:53:30 UTC 2022
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dc.source.uri 10.1021/om300135f
dc.subject.disciplines Chemistry
dc.title Olefin Cyclopropanation Catalyzed by Iridium(III) Porphyrin Complexes
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication d17ef200-84b4-46b1-94f3-67cc67f0a33f
relation.isOrgUnitOfPublication 42864f6e-7a3d-4be3-8b5a-0ae3c3830a11
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