Iron-catalyzed deoxygenation and 2-sulfonylation of quinoline N-oxides by sodium sulfinates towards 2-sulfonyl quinolines

Abstract

An iron(III)-catalyzed protocol towards 2-sulfonyl quinolines from quinoline N-oxides and sodium sulfinates was herein illustrated. The general and direct option featured for high efficiency (up to 91% yields) and good functional compatibilities (27 examples) in the Fe(III)-catalysis. Moreover, free radical mechanism was proposed for the one-pot deoxygenation and sulfonylation reaction based on the results of the control reactions.

Graphical Abstract

An novel reaction between quinoline N-oxides and sodium sulfinates for the synthesis of 2-sulfonyl quinolines was herein achieved by an iron(III)-catalyzed system. The general and direct transformation exhibited high efficiency (up to 91% yields) and good functional-groups compatibilities (27 examples). Moreover, free radical mechanism was proposed for the one-pot deoxygenation and sulfonylation reaction based on the results of the control reactions.

Keywords:

• Iron catalysis
• deoxygenation
• 2-sulfonylation
• quinoline N-oxides
• sodium sulfinates

Acknowledgments

The authors are grateful for the financial support from the Natural Science Foundation of Hunan Province (grant No. 2017JJ3027), the Fundamental Research Funds for Hunan University (grant No. 531107040840).

Additional information

Funding

The authors are grateful for the financial support from the Natural Science Foundation of Hunan Province (grant No. 2017JJ3027), the Fundamental Research Funds for Hunan University (grant No. 531107040840).