Cascade <i>in Situ</i> Iodination, Chromone Annulation, and Cyanation for Site-Selective Synthesis of 2-Cyanochromones
Yan Lin, Jie‐Ping Wan, Yunyun Liu
Abstract
A facile cascade reaction for the site selective synthesis of 2-cyanochromones is described. By using simple o -hydroxyphenyl enaminones and potassium ferrocyanide trihydrate (K 4 [Fe(CN) 6 ] 3 ·3H 2 O) as starting materials and I 2 /AlCl 3 as promoters, the products are furnished via tandem chromone ring formation and C–H cyanation. The in situ formation of 3-iodochromone and a formal 1,2-hydrogen atom transfer (HAT) process account for the unconventional site selectivity. In addition, the synthesis of 2-cyanoquinolin-4-one has been realized by employing corresponding 2-aminophenyl enaminone as substrate.
Topics & Concepts
ChemistryChromoneCyanationAnnulationHalogenationSelectivityRing (chemistry)TandemCascadeCombinatorial chemistryStereochemistryCascade reactionSubstrate (aquarium)Medicinal chemistryOrganic chemistryCatalysisMaterials scienceComposite materialChromatographyGeologyOceanographySynthesis of Organic CompoundsSynthesis of heterocyclic compoundsCatalytic C–H Functionalization Methods