A New Method for the Introduction of an Acylsulfonamide Moiety Applied to a 3-Substituted Functionalized Indole Framework ­Related to the Welwitindolinone Alkaloids

Abstract

The one-pot reaction between an α-formylcyclohexanone derivative and tosyl azide in the presence of rhodium trifluoroacetate dimer afforded an acylsulfonamide derivative. This transformation is proposed to arise from a domino mechanism involving the in situ generation, through the Regitz method, of an α-diazoketone, followed by its transformation into a rhodium carbenoid and its combination with N-tosylformamide, generated as a side product of the first step of the mechanism. Overall, this transformation leads to the generation of a C–N bond between the formyl carbon and the azide nitrogen adjacent to the sulfonyl group.