Straightforward access and easy functionalization of naphtha- and anthradithiophenes

Acenes have optical and electronic properties that are desirable for applications in organic-based electronic devices such as organic field-effect transistors (OFETs) and organic light-emitting diodes (OLEDs). Incorporating heteroarenes, such as thiophene, into these frameworks is part of an ongoing effort to prepare new materials with improved device performances [1]. In this communication we will describe a simple strategy for the preparation of naphtha- and anthradithiophenes that exploits easily available alkylaryl- or diarylalkynes as starting materials and two consecutive one-pot electrophilic processes for the introduction of the sulfur atom and the closure of the thiophene ring. This procedure allows the preparation of 3-chloro-substituted thioacene derivatives that can be further functionalised, with different metal catalysed cross coupling reactions, taking advantage of the heterocyclic carbon-chlorine bond [2]. The applicability, limitation and scope of this new procedure, as well as the reasonable mechanisms involved in the transformation will be presented. [1] See for example: a) H. Dong, C. Wang and W. Hu, Chem. Commun., 46, 2010, 5211 and references cited therein; b) F. Cicoira, C. Santato, M. Melucci, L. Favaretto, M. Gazzano, M. Muccini and G. Barbarella, G. Adv. Mater. 18, 2006, 169; c) J. Laquindanum, H.E. Katz, A.J. Lovinger, J. Am. Chem. Soc. 120, 1998, 664 [2] a) G. Capozzi, F. De Sio, C. Nativi, S. Menichetti, P.L. Pacini, Synthesis 1994, 521; b) G. Lamanna, S. Menichetti Adv. Synth. Catal., 349, 2007, 2188.