Efficient pseudo-five-component coupling-Fiesselmann synthesis of luminescent oligothiophenes and their modification.

(Hetero)aryl bis-acid chlorides and terminal alkynes, or likewise acid chlorides and terminal dialkynes, and ethyl 2-mercaptoacetate can be reacted to give highly luminescent symmetrical terthiophenes and quinquethiophenes in the sense of a consecutive pseudo-five-component reaction in good to excellent yields. Further functionalization of the obtained oligomers can be readily achieved by halogenation followed by a metal-catalyzed coupling reaction to give α,ω-diester substrates for subsequent transformations into highly functionalized materials.