Synthesis of indenothiophenone derivatives by cycloaromatization of non-conjugated thienyl tetraynes

Non-conjugated thienyl tetrayne derivatives 1–3 are prepared as novel building block for the construction of indenothiophenone derivatives. Oxidation of 1–3, followed by cycloaromatization of the corresponding ketone derivatives 13–15 proceeds smoothly to afford indenothiophenone derivatives 16–21 in good yields.