Rongalite as Sulfone Source: A Novel Copper-Catalyzed Sulfur Dioxide Anion Incorporation Process

A novel copper-catalyzed sulfur dioxide anion incorporation cascade for the synthesis of 1-thiaflavanone sulfones has been disclosed using rongalite as an economic and safe sulfone source. A series of 1-thiaflavanone sulfones were synthesized from easily prepared 2′-iodochalcone derivatives in excellent yields. This transformation proceeds through consecutive formation of two C–S bonds, which is the first example of SO22− being used to construct sulfone motifs under copper-catalyzed conditions.