Photostimulated SRN1 Reactions of Halothiophenes with Benzenethiolate Ion in Acetonitrile

Article abstract of DOI:10.1021/jo00233a014

The photostimulated reactions between benzenethiolate and 2-chloro-, 2-bromo-, 2-iodo-, and 3-bromothiophene in MeCN lead to rather complex product mixtures where the phenyl thienyl sulfide(ThSPh), the ipso-substitution product, represents the main component.The collected results agree well with the occurrence of an S_RN1 chain pathway.As to the obtainable yield of sulfide, the main drawback is represented by the fragmentation into ThS^- and Ph(radical) of the ThSPh radical anion, formeded either along the propagation cycle or by single-electron reduction of the sulfide itself.Optimization of the yield of ThSPh, although at the expense of the overall reaction rate, can be achieved by the employment of suitable electron acceptors.The overall reactivity orders (2-I > 2-Br > 2-Cl and 2-Br > 3-Br) are also discussed.