• In organic chemistry, umpolung (German: [ˈʔʊmˌpoːlʊŋ]) or polarity inversion is the chemical modification of a functional group with the aim of the reversal...
    14 KB (1,784 words) - 14:56, 20 August 2024
  • The Corey–Seebach reaction, or Seebach Umpolung is a name reaction of organic chemistry that allows for acylation by converting aldehydes into lithiated...
    7 KB (770 words) - 22:22, 27 September 2024
  • Polarity inversion may refer to: Polarity inversion (chemistry) (aka Umpolung), in organic chemistry Polarity inversion (differential pairs), swapping...
    331 bytes (64 words) - 21:04, 25 February 2022
  • forget about their language and their origin. As a neologism, it echoes Umpolung, 'polarity inversion', leading to an interpretation akin to "ethnicity...
    3 KB (350 words) - 01:46, 26 September 2024
  • Thumbnail for Benzoin condensation
    Aldol addition Acyloin condensation Cannizzaro reaction Stetter reaction Umpolung Menon, Rajeev S.; Biju, Akkattu T.; Nair, Vijay (2016). "Recent advances...
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  • inversion of polarity between R'(H)Cδ+=Oδ− and R'CLi(SR)2 is referred to as umpolung. The reaction is commonly performed using the 1,3-dithiane. The lithiated...
    3 KB (377 words) - 00:26, 11 December 2023
  • Thumbnail for Pyruvate dehydrogenase complex
    produce an acyl anion equivalent (see cyanohydrin or aldehyde-dithiane umpolung chemistry, as well as benzoin condensation). This anion attacks S1 of an...
    29 KB (3,340 words) - 20:01, 15 August 2024
  • Thumbnail for Thiamine
    Boluda CJ, Juncá C, Soto E, de la Cruz D, Peña A (13 December 2019). "Umpolung in reactions catalyzed by thiamine pyrophosphate dependent enzymes". Ciencia...
    58 KB (5,764 words) - 04:05, 22 October 2024
  • Thumbnail for Homoenolates
    chemistry since the 1980s. They are related to enolates, but represent an umpolung of their reactivity. Homoenolates can be formed with a variety of different...
    3 KB (277 words) - 16:34, 21 February 2024
  • Thumbnail for Mercury(II) chloride
    chloride is used to remove dithiane groups attached to a carbonyl in an umpolung reaction. This reaction exploits the high affinity of Hg2+ for anionic...
    29 KB (3,120 words) - 21:01, 4 April 2024
  • triazolium salts to be effective. The Stetter reaction is an example of umpolung chemistry, as the inherent polarity of the aldehyde is reversed by the...
    19 KB (2,357 words) - 19:34, 9 March 2023
  • Thumbnail for Propane-1,3-dithiol
    formaldehyde. The reactivity of this dithiane illustrates the concept of umpolung. Alkylation gives thioethers, e.g. 1,5-dithiacyclooctane. The unpleasant...
    5 KB (273 words) - 04:13, 13 August 2023
  • They represent a subclass of sulfides. The thioacetals are useful in "umpolung" of carbonyl groups. Thioacetals and thioketals can also be used to protect...
    26 KB (3,035 words) - 15:33, 11 July 2024
  • Thumbnail for Dithiane
    of Hg(II) for thiolates. 1,3-Dithianes are more importantly employed in umpolung reactions, such as the Corey–Seebach reaction: 1,4-Dithiane is an organosulfur...
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  • Thumbnail for Elias James Corey
    reactivity in displacement and addition reactions. Dithianation introduced umpolung chemistry, now a key concept in organic synthesis. The formations of dithianes...
    55 KB (5,643 words) - 23:27, 3 November 2024
  • Thumbnail for Persistent carbene
    S.; Yatham V. R.; Neudörfl J.-M.; Schlörer N. E.; Teles J. H. (2012). "Umpolung by N-Heterocyclic Carbenes: Generation and Reactivity of the Elusive 2...
    62 KB (6,933 words) - 11:59, 13 August 2024
  • Thumbnail for Dithiol
    resulting anion can be C-alkylated. The process is the foundation of the umpolung phenomenon. Like 1,2-ethanedithiol, propanedithiol forms complexes with...
    5 KB (524 words) - 17:06, 27 April 2023
  • apparatus Meitnerium Mischmetall (lit. "mixed metal"), alloy Roentgenium Umpolung (organic chemistry) Wolfram Zwitterion Allumwandlung Blitz chess, from...
    62 KB (7,175 words) - 02:39, 24 October 2024
  • Thumbnail for Dieter Seebach
    chemistry and on the synthesis of beta-peptides. The development of the umpolung, a polarity inversion of the carbonyl group, with 1,3-propanedithiol together...
    4 KB (297 words) - 19:31, 12 October 2023
  • diazaphospholenes (scheme 3), the polarity of the P-H bond can be inverted (see: umpolung) and the resulting phosphine hydride can reduce a carbonyl group as in...
    16 KB (1,699 words) - 02:29, 19 June 2024
  • Taylor, Carol M. (2006-08-01). "β-Glycosides of Hydroxyproline via an Umpolung Approach". Organic Letters. 8 (18): 3959–3962. doi:10.1021/ol061424m. ISSN 1523-7060...
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  • Thumbnail for Stereoelectronic effect
    W.; Shevchenko, Nikolay; Alabugin, Igor V. (2013). ""Stereoelectronic Umpolung": Converting a p-Donor into a σ-Acceptor via Electron Injection and a Conformational...
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  • (NHCs) are an emerging class of organocatalysts that are able to induce Umpolung reactivity as well as normal polarity transformations, however until recently...
    13 KB (1,714 words) - 07:15, 3 October 2023
  • intermediates may also intercept nucleophiles in a process that involves umpolung at the α carbon. In addition, because reduction of monohalo ketones produces...
    10 KB (1,241 words) - 19:10, 27 June 2024
  • S2CID 11653420. Dai, Xijie; Li, Chenchen; Li, Chao-Jun (April 2021). "Carbonyl umpolung as organometallic reagent surrogates". Chemical Society Reviews. 50 (19):...
    13 KB (1,308 words) - 02:21, 4 September 2024
  • Thumbnail for Bis(cyclopentadienyl)titanium(III) chloride
    PMID 15543313. Streuff, Jan (2011). "A titanium(III)-catalyzed redox Umpolung reaction for the reductive cross-coupling of enones with acrylonitriles"...
    24 KB (2,292 words) - 12:01, 21 May 2024
  • formation of the other allylic analog by logic similar to cyanide-type umpolung. It then later provides a good leaving group for formation of the iminium...
    50 KB (5,704 words) - 20:45, 22 July 2024
  • doi:10.1038/nchem.1607. Xavier Bugaut, Frank Glorius: Organocatalytic umpolung: N-heterocyclic carbenes and beyond. In: Chemical Society Reviews. 41,...
    10 KB (1,069 words) - 01:46, 5 October 2024