Didehydroisobenzothiophene: a new reactive intermediate for the construction of isoacenothiophene

Abstract An efficient method for the generation of a new heteroaryne species, didehydroisobenzothiophene, was developed by bromine–lithium exchange of the dibromoisobenzothiophene. The generated reactive intermediate was cyclized with arynophiles to give the [2 + 2] and [2 + 4] cycloadducts, respectively. Furthermore, the reaction was applied to synthesize isoanthracenothiophene (anthra[2,3-c]thiophene), a novel heteroacene having isoelectoronic structure with the corresponding acenoheterole (anthra[2,3-b]thiophene).