Bismuth(III)‐Promoted Acetylation of Thioethers into Thioacetates. Issue 21 (15th June 2015) - Jevric, Martyn
Abstract: The thioacetate group is extensively employed as an anchoring group for attachment of molecules onto gold surfaces or between electrodes in molecular electronics. On account of its ready hydrolysis, it is often incorporated in the last step of a synthetic sequence from the corresponding tert ‐butyl thioether. Here we present a particularly convenient method for this conversion using AcCl in combination with Bi(OTf)3, which is known as an environmentally friendly salt. A large variety of redox‐active and photoactive substrates with tert ‐butyl thioether end‐cap(s) was prepared, including molecules incorporating dithiafulvene, dicyanoethylene, dihydroazulene, fulleropyrrolidine, and triazole units, and successfully subjected to a Bi III promoted conversion into products with thioacetate end‐cap(s). The azide group could also withstand these conditions, which allowed us to prepare S ‐(4‐azidophenyl) ethanethioate that presents a convenient building block for subsequent CuAAC reactions. Abstract : Conversion of tert ‐butyl thioethers into thioacetates is conveniently performed by the action of acetyl chloride and bismuth(III) triflate. The thioacetate group is extensively employed as electrode anchoring group in molecular electronics, and we show that these gentle conditions allow the preparation of a large selection of target molecules of interest as molecular wires.