Amos Stephanie G E, Cavalli Diana, Le Vaillant Franck, Waser Jerome
Laboratory of Catalysis and Organic Synthesis and National Centre of Competence in Research (NCCR) Catalysis, Institut des Sciences et Ingénierie Chimique, Ecole Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland.
Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, 45470, Germany.
Angew Chem Int Ed Engl. 2021 Oct 25;60(44):23827-23834. doi: 10.1002/anie.202110257. Epub 2021 Sep 21.
Ethynylbenziodoxolones (EBXs) are commonly used as radical traps in photocatalytic alkynylations. Herein, we report that aryl-substituted EBX reagents can be directly activated by visible light irradiation. They act as both oxidants and radical traps, alleviating the need for a photocatalyst in several reported EBX-mediated processes, including decarboxylative and deboronative alkynylations, the oxyalkynylation of enamides and the C-H alkynylation of THF. Furthermore, the method could be applied to the synthesis of alkynylated quaternary centers from tertiary alcohols via stable oxalate salts and from tertiary amines via aryl imines. A photocatalytic process using 4CzIPN as an organic dye was also developed for the deoxyalkynylation of oxalates.
乙炔基苯碘恶唑酮（EBXs）通常用作光催化炔基化反应中的自由基捕获剂。在此，我们报道芳基取代的EBX试剂可通过可见光照射直接活化。它们兼具氧化剂和自由基捕获剂的作用，在一些已报道的EBX介导的反应中无需光催化剂，这些反应包括脱羧和脱硼炔基化反应、烯酰胺的氧炔基化反应以及四氢呋喃的C-H炔基化反应。此外，该方法可用于通过稳定的草酸盐由叔醇合成炔基化季碳中心，以及通过芳基亚胺由叔胺合成炔基化季碳中心。还开发了一种以4CzIPN作为有机染料的光催化方法用于草酸盐的脱氧炔基化反应。
