A new strategy for effecting cascade cyclization processes using nickel enolates has been developed. Nickel enolates may be cleanly generated by the oxidative cyclization of an enal and alkyne with Ni(0), and the resulting enolate may be functionalized by a variety of alkylation processes. Partially and fully intramolecular versions of the process allow the rapid synthesis of complex polycyclics from simple achiral, acyclic precursors.
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPermercuration of Ferrocenes and Ruthenocenes. New Approaches to Complexes Bearing Perhalogenated Cyclopentadienyl LigandsYoung-Hee Han, Mary Jane Heeg, and Charles H. WinterCite this: Organometallics 1994, 13, 8, 3009–3019Publication Date (Print):August 1, 1994Publication History Published online1 May 2002Published inissue 1 August 1994https://pubs.acs.org/doi/10.1021/om00020a017https://doi.org/10.1021/om00020a017research-articleACS PublicationsRequest reuse permissionsArticle Views382Altmetric-Citations46LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts
A new pyridine-based bidentate ligand LPyC18 was used to develop copper-containing surfactants that exhibit mesomorphism. Complexes [(LPyC18)2CuIIY]Y were synthesized, where Y is an anionic ligand bromo (1), nitrato (2), or perchlorato (3). The nature of these apical ligands determines the mesogenic behavior of 1−3: The smallest bromo-substituted species 1 shows a metastable liquid crystalline phase at 110 °C, the nitrato-substituted 2 increases the transition temperature to 136 °C, and the bulky perchlorato-substituted 3 shows reversible mesophases at 153 °C. The behavior of these complexes shows similarities and suggests that at low temperatures the crystals of these compounds are bilayered structures with interdigitated alkyl tails. At higher temperatures the tails undergo rapid conformational changes that force these layers to swell until the opposing alkyl chains are separated from each other, and the mesophase is a monolayer smectic A. Small changes in the geometry of cationic mesogens can be imposed by the presence of apically coordinated anions, allowing for tuning in the properties of the resulting mesophases.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA Unified Entry into the Ingenane, Tigliane, and Taxane Ring SystemsJames H. Rigby, Noormohamed M. Niyaz, Kevin Short, and Mary Jane HeegCite this: J. Org. Chem. 1995, 60, 24, 7720–7721Publication Date (Print):December 1, 1995Publication History Published online1 May 2002Published inissue 1 December 1995https://pubs.acs.org/doi/10.1021/jo00129a006https://doi.org/10.1021/jo00129a006research-articleACS PublicationsRequest reuse permissionsArticle Views302Altmetric-Citations31LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (2)»Supporting Information Supporting Information Get e-Alerts
Give me five! Two five-coordinate complexes of iron with geometries that are based on those found in redox-versatile enzymes have been synthesized. The phenolate-rich, pentadentate N2O3 phenylene–diamine/triphenolate ligands confer a low local symmetry on the complex so that only subtle modifications in the structure of the ligands are sufficient to completely change the sequence in which the metal and the ligands are oxidized (see scheme).
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and characterization of polypyridine ruthenium(II) complexes containing S-bonded thioether ligands. X-ray crystal structures of cis- and trans-bis(2,2'-bipyridine)bis(phenothiazine-S)ruthenium(II) hexafluorophosphatesRudi Kroener, Mary Jane Heeg, and Edward DeutschCite this: Inorg. Chem. 1988, 27, 3, 558–566Publication Date (Print):February 1, 1988Publication History Published online1 May 2002Published inissue 1 February 1988https://pubs.acs.org/doi/10.1021/ic00276a024https://doi.org/10.1021/ic00276a024research-articleACS PublicationsRequest reuse permissionsArticle Views366Altmetric-Citations42LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts
Studies have been conducted on the copper complexes formed with two sexadentate macrocyclic ligands containing four thioether sulfur donor atoms plus either two nitrogen or two oxygen donor atoms on opposing sides of the ring. The resulting two ligands, L, designated as [18]aneS(4)N(2) and [18]aneS(4)O(2), respectively, represent homologues of the previously studied Cu(ii/i) system with a macrocycle having six sulfur donor atoms, [18]aneS(6). Crystal structures of [Cu(II)([18]aneS(4)O(2))](ClO(4))(2) and [Cu(I)([18]aneS(4)O(2))]ClO(4) have been determined in this work. Comparison of the structures of all three systems reveals that the oxidized complexes are six coordinate with two coordinate bonds undergoing rupture upon reduction. However, the geometric changes accompanying electron transfer appear to differ for the three systems. The stability constants and electrochemical properties of both of the heteromacrocyclic complexes have been determined in acetonitrile and the Cu(II/I)L electron-transfer kinetics have been studied in the same solvent using six different counter reagents for each system. The electron self-exchange rate constants have then been calculated using the Marcus cross relationship. The results are compared to other Cu(II/I)L systems in terms of the effect of ligand geometric changes upon the overall kinetic behavior.
ADVERTISEMENT RETURN TO ISSUEPREVArticleSynthesis and characterization of cationic technetium complexes of 1,2-bis(dimethylphosphino)ethane (DMPE). Structure determinations of trans-[TcV(DMPE)2(OH)(O)](F3CSO3)2, trans-[TcIII(DMPE)2Cl2]F3CSO3, and [TcI(DMPE)3]+ using x-ray diffraction, EXAFS, and technetium-99 NMR [Erratum to document cited in CA101(16):142794q]Jean Luc Vanderheyden, Alan R. Ketring, Karen Libson, Mary Jane Heeg, Lee Roecker, Philip Motz, Robert Whittle, R. C. Elder, and Edward DeutschCite this: Inorg. Chem. 1990, 29, 23, 4840Publication Date (Print):November 1, 1990Publication History Published online1 May 2002Published inissue 1 November 1990https://pubs.acs.org/doi/10.1021/ic00348a052https://doi.org/10.1021/ic00348a052research-articleACS PublicationsRequest reuse permissionsArticle Views24Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
