合成路线1

In an alternative procedure, the bithiophene aldehyde (II) was reduced to alcohol (VII) with NaBH4, and this was protected with dihydropyran to give (VIII). Lithiation and subsequent treatment of (VIII) with tributyltin chloride afforded the stannyl compound (IX). This was then coupled with 2-bromo-4-thiophene-carboxaldehyde (X) in the presence of Pd(PPh3)4 and an additional amount of PPh3 to provide the terthiophene (XI). The reduction of the aldehyde group of (XI) with NaBH4, and then acid hydrolysis of the tetrahydropyranyl protecting group furnished diol (XII). Finally, the oxidation of (XII) by means of DDQ gave rise to a 1:3 mixture of the desired hydroxy aldehyde and its regioisomer (XIII).