Rapid Access to Benzimidazo[1,2-<i>a</i>]quinoline-Fused Isoxazoles via Pd(II)-Catalyzed Intramolecular Cross Dehydrogenative Coupling: Synthetic Versatility and Photophysical Studies
Subrata Sahoo, Shantanu Pal
Abstract
An efficient and atom-economical palladium-catalyzed intramolecular cross dehydrogenative coupling (CDC) reaction has been developed for the construction of highly π-conjugated benzimidazo[1,2-a]quinoline-fused isoxazole scaffolds using molecular oxygen as sole oxidant. The approach portrayed wide substrate scope with good functional group tolerance and depicted a useful tool for the generation of fluorescence active compounds with high quantum yield. Synthetic versatility of the method via Fe-catalyzed reductive isoxazole ring cleavage toward pyridine, pyrimidine, pyrazole fused heteropolycyclic compounds has been showcase.
Topics & Concepts
IsoxazoleIntramolecular forceQuinolineChemistryPyridineCombinatorial chemistryConjugated systemRing (chemistry)CatalysisPyrazolePhotochemistryStereochemistryMedicinal chemistryOrganic chemistryPolymerCatalytic C–H Functionalization MethodsCatalytic Cross-Coupling ReactionsSulfur-Based Synthesis Techniques