Affiliation:
1. Institute of Organic Chemistry Karlsruhe Institute of Technology Fritz-Haber-Weg 6 76131 Karlsruhe Germany
2. Department of Chemistry University of Zurich Winterthurerstr. 190 8057 Zürich Switzerland
Abstract
AbstractN,O‐acetals are found as structural motifs in natural products and are important synthetic precursors for N‐acylimines as building blocks in organic synthesis for C−C‐bond formation and amines. For the synthesis of N,O‐acetals, an acid‐, base‐ and metal‐free catalytic method is reported applying N,N‐di‐(2,6‐diisopropyl)‐1,7‐dicyano‐perylen‐3,4,9,10‐tetracarboxylic acid imide and N,N‐di‐(2,6‐diisopropyl)‐1,6,7,12‐tetrabromo‐2,5,8,11‐tetracyano‐perylen‐3,4,9,10‐tetracarboxylic acid imide as extremely electron‐deficient photocatalysts. The first perylene bisimide highly selectively photocatalyzes the formation of the N,O‐acetals as products in high yields, and the second and more electron‐deficient perylene bisimide allows these reactions without thiophenol as an H‐atom transfer reagent. Calculated electron density maps support this. The reaction scope comprises different substituents at the nitrogen of the enamides and different alcohols as starting material. Dehydroalanines are converted to non‐natural amino acids which shows the usefulness of this method for organic and medicinal chemistry.
Funder
Deutsche Forschungsgemeinschaft
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung