title: Synthesis of unsymmetrical thioethers using an uncommon base-triggered 1,5-thiol transfer reaction of 1-bromo-2-alkylthiolcarbonates.
abstract: Described herein is a convenient, odorless, metal-free, one-pot strategy for the synthesis of unsymmetrical thioethers. The key step in this new strategy is a base-catalyzed 1,5-thiol transfer reaction via a pseudointramolecular mechanism of a 1-bromo-2-alkylthiolcarbonate, which is itself obtained through a straightforward microwave-assisted thioalkylation of a 1,2-cyclic-thionocarbonate precursor with an appropriate alkyl bromide. The starting 1,2-cyclic-thionocarbonates are easily obtained from the corresponding diols. When a propargylthiolcarbonate constitutes the key alkylthiolcarbonate 1,5-shift precursor, a copper-mediated dipolar cycloaddition reaction ("click") with azide partners is rendered possible. This increases the versatility of the approach, as a very large variety of complex triazole-tethered substrates can potentially be integrated into the target unsymmetrical thioether final products. As an example of the scope of the reaction, four 1,5-shift reactions have been triggered simultaneously from a sugar-derived tetrathiolcarbonate precursor using base catalysis, to allow four 6-thioglucose moieties to be installed (78% yield for each sugar unit) onto a 1,3-alternate thiacalix[4]arene scaffold in a one-pot transformation.
authors.affiliation: Laboratoire de Glycochimie, des Antimicrobiens et des Agroressources (LG2A-FRE3517 CNRS), Université de Picardie Jules Verne , 10 Rue Baudelocque 80039, Amiens Cédex, France.
authors.forename: Marwa
authors.initials: M
authors.lastname: Taouai
authors.forename: Rym
authors.initials: R
authors.lastname: Abidi
authors.forename: Julien
authors.initials: J
authors.lastname: Garcia
authors.forename: Aloysius
authors.initials: A
authors.lastname: Siriwardena
authors.forename: Mohammed
authors.initials: M
authors.lastname: Benazza
mesh_terms: D000473:Alkanes / Q000737:chemistry*; D001386:Azides / Q000737:chemistry; D002241:Carbohydrates / Q000737:chemistry*; D002384:Catalysis; D061565:Cycloaddition Reaction; D006842:Hydrocarbons, Brominated / Q000737:chemistry; D010636:Phenols / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013440:Sulfides / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000473:Alkanes; D001386:Azides; D002241:Carbohydrates; D006842:Hydrocarbons, Brominated; D010636:Phenols; D013438:Sulfhydryl Compounds; D013440:Sulfides; C500450:thiacalix(4)arene