A theoretical approach to the formation mechanism of diphenyldithieno[3, 2-b:2 ',3 '-d]thiophene from 1,8-diketone, 4,5-bis(benzoylmethylthio)thiophene: a DFT study


Ozen C., YURTSEVER M., Öztürk T.

TETRAHEDRON, vol.67, no.34, pp.6275-6280, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 67 Issue: 34
  • Publication Date: 2011
  • Doi Number: 10.1016/j.tet.2011.06.037
  • Journal Name: TETRAHEDRON
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.6275-6280
  • Istanbul Technical University Affiliated: Yes

Abstract

The mechanism of formation of dithieno[3,2-6:2',3'-d]thiophene (DTT) through the reaction of 1,8-diketone, 4,5-bis(benzoylmethylthio)thiophene with P(4)S(10) was examined in detail by employing DFT method at B3LYP/6-311+G(d,p) level. Two mechanisms were considered. The first one included two parts (i) transformation of the 1,8-diketone, 4,5-bis(benzoylmethylthio)thiophene to the dithione by the reaction of P(4)S(10) with the carbonyl groups and (ii) cyclization of the dithione to the final product, DTT, through an intramolecular reaction of the thiophene with thiones. The second mechanism consists of an initial attack of the carbonyl oxygen to the phosphorus atom of P(4)S(10) followed by cyclization via an intramolecular attack from the thiophene ring to the highly electrophilic carbons connected to the oxygens to form DTT. According to the calculated Gibbs free energies of the studied paths, the second mechanism is more favorable than the first one and both pathways proceed in a stepwise manner. (C) 2011 Elsevier Ltd. All rights reserved.