Fluorescent 3-Methylene-2,3-Dihydrochalcogenophenes Incorporated in a Rigid Dibenzobarrelene Skeleton

The fluorescent 3-methylene-2,3-dihydroselenophene derivative (ΦF = 0.86 in CH2Cl2) incorporated in a dibenzobarrelene skeleton was synthesized by the reaction of a four-membered selenaplatinacycle with dimethyl acetylenedicarboxylate (DMAD) or reaction of bis(dibenzobarrelenyl) diselenide with DMAD in the presence of Pd(PPh3)4 and PPh3. A fluorescent sulfur homologue (ΦF = 1.0 in CH2Cl2) was also synthesized by the reaction of bis(dibenzobarrelenyl) disulfide with DMAD in the presence of Pd(PPh3)4. Selected chemical transformations of these diesters were also investigated.