title: A recyclable and base-free method for the synthesis of 3-iodothiophenes by the iodoheterocyclisation of 1-mercapto-3-alkyn-2-ols in ionic liquids.
abstract: The first example of an iodocyclisation reaction made recyclable by the use of an ionic liquid as the reaction medium is reported. Readily available 1-mercapto-3-alkyn-2-ols were smoothly converted into the corresponding 3-iodothiophenes (50-81% yields, 10 examples) when allowed to react with iodine (1-2 equiv.) in a proper ionic liquid, such as 1-ethyl-3-methylimidazolium ethyl sulfate (EmimEtSO4), as the solvent under mild reaction conditions (25 °C) and in the absence of an external base. The reaction medium can be recycled several times without significantly affecting the reaction outcome. Theoretical calculations have also been performed to investigate the role of the ionic liquid anion in the reaction.
authors.affiliation: Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Via P. Bucci, 12/C, 87036 Arcavacata di Rende (CS), Italy. raffaella.mancuso@unical.it bartolo.gabriele@unical.it.
authors.forename: Raffaella
authors.initials: R
authors.lastname: Mancuso
authors.forename: Christian S
authors.initials: CS
authors.lastname: Pomelli
authors.forename: Cinzia
authors.initials: C
authors.lastname: Chiappe
authors.forename: Richard C
authors.initials: RC
authors.lastname: Larock
authors.forename: Bartolo
authors.initials: B
authors.lastname: Gabriele
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D003500:Cyclization; D052578:Ionic Liquids / Q000737:chemistry*; D015394:Molecular Structure; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013876:Thiophenes / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000480:Alkynes; D052578:Ionic Liquids; D013438:Sulfhydryl Compounds; D013876:Thiophenes