Switching of Sulfonylation Selectivity by Nature of Solvent and Temperature: The Reaction of β‐Dicarbonyl Compounds with Sodium Sulfinates under the Action of Iron‐Based Oxidants

Abstract

Selectivity of sulfonylation of β‐keto esters with sodium sulfinates under the action of iron(III) salts as oxidants can be regulated by the type of solvent used and the reaction temperature. α‐Sulfonyl β‐keto esters are obtained when the process is conducted in THF/H 2 O solution at 40 °C. The change of the solvent to i PrOH/H 2 O and refluxing of a reaction mixture provides α‐sulfonyl esters – the products of successive sulfonylation‐deacylation. When β‐diketones are applied as starting materials, only α‐sulfonyl ketones are formed. The reaction pathway includes sulfonylation of dicabonyl compounds under the action of Fe(III) to form α‐sulfonylated dicarbonyl compounds, which are then attacked by a solvent as the nucleophile, resulting in the products of successive sulfonylation‐deacylation. Participation of the solvent in the reaction pathway determines the products structure.