N,N-Dialkylhydrazones as Versatile Umpolung Reagents in Enantioselective Anion-Binding Catalysis
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Angewandte Chemie Intl Edit - 2020 - G mez‐Mart nez - N N‐Dialkylhydrazones as Versatile Umpolung Reagents in.pdf (1.93 MB)
Date
2020-12-11
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Wiley-VCH on behalf of Chemistry Europe
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Abstract
An enantioselective anion-binding organocatalyticapproach with versatile N,N-dialkylhydrazones (DAHs) aspolarity-reversed (umpolung) nucleophiles is presented. Forthe application of this concept, a highly ordered hydrogen-bond (HB) network between a carefully selected CF3-substi-tuted triazole-based multidentate HB-donor catalyst, the ionicsubstrate and the hydrazone in a supramolecular chiral ion-pair complex was envisioned. The formation of such a networkwas further supported by both experimental and computationalstudies, which showed the crucial role of the anion as a templateunit. The asymmetric Reissert-type reaction of quinolines asa model test reaction chemoselectively delivered highly enan-tiomerically enriched hydrazones (up 95:5 e.r.) that could befurther derivatized to value-added compounds with up to threestereocenters.
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Angew. Chem.2021,133, 5162 –5167