Categories: C-S Bond Formation >
Synthesis of sulfonamides
The bench-stable colorless solid charge-transfer complex generated from the combination of DABCO and sulfur dioxide, DABSO, can replace gaseous sulfur dioxide in organic synthesis. Reactions with Grignard reagents form sulfinates, which can then be converted in situ to sulfonamides. Alternatively, reaction with anilines and iodine leads to the formation of a series of sulfamides.
H. Woolven, C. Gonzáles-Rodríguez, I. Marco, A. L. Thompson, M. C. Willis, Org. Lett., 2011, 13, 4876-4878.
A simple copper-catalyzed aminosulfonylation of aryldiazonium tetrafluoroborates, DABCO·(SO2)2, and N-chloroamines provides a wide range of sulfonamides in good yields under mild conditions. Mechanistic investigation suggests that a radical process and transition-metal catalysis take place.
F. Zhang, D. Zheng, L. Lai, J. Cheng, J. Sun, J. Wu, Org. Lett., 2018, 20, 1167-1170.
A Pd-catalyzed coupling of aryl iodides and the sulfur dioxide surrogate DABSO provides aryl ammonium sulfinates, that can be transformed in a one-pot process to various functionalized sulfonamides by simple treatment with an aqueous solution of the relevant amine and sodium hypochlorite (bleach). A broad range of amines, including anilines, and amino acid derivatives can be used.
E. F. Flegeau, J. M. Harrison, M. C. Willis, Synlett, 2016, 27, 101-105.