A concise synthesis of tunable fluorescent 1,3-dihydroisobenzofuran derivatives as new fluorophores

Abstract

A convenient potassium tert-butoxide catalyzed addition–elimination reaction has been achieved using exo-cyclic enol ethers and aryl aldehydes as the starting materials. The transition-metal free reaction proceeded smoothly to afford 1,3-dihydroisobenzofuran derivatives with good to excellent yields. More importantly, the resulting products were discovered as novel fluorophores with good fluorescence properties and remarkable Stokes shifts. Changing the nature of the substituents in 1,3-dihydroisobenzofurans derivatives allowed the maximum emission wavelengths to be tuned between 438 and 597 nm and the Stokes shifts varied between 63 and 166 nm. In particular, derivative C27 containing a piperidyl and a cyano group showed the maximum emission wavelength of 597 nm and a Stokes shift of 166 nm.