Copper-Catalyzed Multicomponent Oxysulfonylation of Alkenes with Cyclobutanone Oxime Esters and Hydroxamic Acids via the Insertion of Sulfur Dioxide

A copper-catalyzed multicomponent oxysulfonylation of alkenes with cyclobutanone oxime esters and hydroxamic acids via the insertion of sulfur dioxide has been developed. This reaction uses K2S2O5 as the sulfur dioxide surrogate and the in situ generated amidoxyl radical as radical interceptor, thus providing a direct approach to beta-amidoxy sulfones in 35-90% yields. Mechanistic studies revealed that a radical-radical coupling reaction of the alkyl radical and amidoxyl radical might be involved in this transformation.

Automated summary

A copper-catalyzed multicomponent oxysulfonylation of alkenes with cyclobutanone oxime esters and hydroxamic acids via the insertion of sulfur dioxide has been developed. This reaction provides a direct approach to β-amidoxy sulfones in 35-90% yields using K2S2O5 as the sulfur dioxide surrogate and the in situ generated amidoxyl radical as radical interceptor. Mechanistic studies suggest the involvement of a radical-radical coupling reaction between the alkyl radical and amidoxyl radical.