SYNTHESIS OF SUBSTITUTED 2,3,5,6-TETRAARYLBENZO[1,2-B-5,4-B']DIFURANS

A series of substituted 2,3,5,6-tetraarylbenzo[1,2-b:5,4-b']difurans 1 was synthesized. This synthesis is based upon the photocyclization of 2,5-dibenzoylresorcinol dibenzyl ethers to the corresponding tetrahydrobenzo[1,2-b:5,4-b']difurans. Treatment of the photoproducts with methanesulfonyl chloride in pyridine afforded 1 in overall yields ranging from 30-72%. A number of these compounds have high fluorescence quantum yields (phi(f) = 0.76-0.90), and their fluorescence spectra exhibit large solvatochromic shifts. These compounds may be suitable for use as fluorescent probes.