Unprecedented Demonstration of Regioselective S sub(E)Ar Reaction giving Unsymmetrical Regioregular Oligothiophenes

• Published in: Chemistry : a European journal Vol. 22; no. 19; pp. 6510 - 6514
• Main Authors: Moussallem, Chady, Olivier, Simon, Grolleau, Jeremie, Allain, Magali, Mallet, Charlotte, Savitha, Gurunathan, Gohier, Frederic, Frere, Pierre
• Format: Journal Article
• Language: English
• Published: 01-05-2016
• Subjects: Alternations; Backbone; Chlorides; Formations; Oligomers
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201600159

Aromatization of 4-cyano-3-oxotetrahydrothiophene by sulfuryl chloride gives the new building block 4-cyano-3-pyrrolidylthiophene, which forms unsymmetrical regioregular oligothiophenes with a strict alternation of the donor and acceptor groups along the conjugated system. The self-coupling reactions that form the oligomers are shown to proceed by a regioselective electrophilic aromatic substitution mechanism involving a stabilized Wheland intermediate. First alternate: Regioregular oligothiophenes based on the 3-pyrrolidyl-4-cyanothiophene building block, with a strict alternation of the donor and acceptor groups along the conjugated backbone, have been prepared in one step. The mechanism of formation of the oligomers corresponds to a regioselective self-electrophilic aromatic substitution (self-S sub(E)Ar) involving a stabilized Wheland intermediate.