An efficient access to ß-ketosulfones via ß-sulfonylvinylamines: metal-organic framework catalysis for the direct C-S coupling of sodium sulfinates with oxime acetates.

A copper-based framework Cu2(OBA)2(BPY) was synthesized and used as a recyclable heterogeneous catalyst for the synthesis of ß-sulfonylvinylamines from sodium sulfinates and oxime acetates via direct C-S coupling reaction. The transformation was remarkably affected by the solvent, and chlorobenzene emerged as the best option. This Cu-MOF displayed higher activity than numerous conventional homogeneous and MOF-based catalysts. The catalyst was reutilized many times in the synthesis of ß-sulfonylvinylamines without considerably deteriorating in catalytic efficiency. These ß-sulfonylvinylamines were readily converted to the corresponding ß-ketosulfones via a hydrolysis step with aqueous HCl solution. To the best of our knowledge, this direct C-S coupling reaction to achieve ß-sulfonylvinylamines was not previously conducted with a heterogeneous catalyst.