Improved synthesis of dithieno[3,2-b : 2 ',3 '-d] thiophene (DTT) and derivatives for cross coupling

An improved synthesis of dithieno[3,2-b: 2',3'-d] thiophene (DTT) and its 2,6- and 3,5- dibromo derivatives has been devised; Stille cross coupling of 2,5-(bistrimethylstannyl) DTT afforded the oligomer 12.