Synthesis of tetracyclic 4H-benzo[5,6]chromeno[3,4-d]oxazoles via palladium-catalyzed intramolecular direct heteroarylation

We report a palladium-catalyzed intramolecular direct heteroarylation of oxazole tethered beta-naphthols to access corresponding tetracyclic 4H-benzo[5,6]chromeno[3,4-d]oxazoles. Various functional groups are well tolerated and furnished the desired products in good to excellent yields under the present reaction conditions. The scale-up reaction and synthetic utility of the resulting molecules have been demonstrated. Moreover, UV/vis absorption and fluorescence emission properties have been evaluated for these polyheterocyclic compounds.

Automated summary

A palladium-catalyzed intramolecular direct heteroarylation of oxazole tethered beta-naphthols to access tetracyclic 4H-benzo[5,6]chromeno[3,4-d]oxazoles is reported. The reaction exhibits good to excellent yields with various functional groups. The resulting molecules show promising synthetic utility and UV/vis absorption and fluorescence emission properties.