The efficient synthesis of dibenzo[<i>d</i>,<i>d</i>′]benzo[1,2-<i>b</i>:4,3-<i>b</i>′]dithiophene and cyclopenta[1,2-<i>b</i>:4,3-<i>b</i>′]bis(benzo[<i>d</i>]thiophen)-6-one
Beilstein journal of organic chemistry