A formal vinylic substitution reaction for the synthesis of ,-unsaturated enol esters and their anticancer potential

Arylsulfonyl group-bearing alpha,beta-unsaturated enol esters were readily assembled via the Cs2CO3-mediated union of 2-bromoallyl sulfones and cinnamic acids. The overall transformation is equivalent to an sp2 carbon-oxygen coupling reaction, and therefore constitutes a formal vinylic substitution. Several of the products display promising levels of antiproliferative activities higher than that of the anticancer drug carboplatin. Thiophenol reacted with 2-bromoallyl sulfones under identical conditions to afford alpha-thiophenyl-alpha '-tosyl acetone via an apparent aerial oxidation. Cesium carbonate promoted a 'formal vinylic substitution' of the bromine in 2-bromoallyl sulfones by alpha,beta-unsaturated acids. The arylsulfonyl group-bearing enol esters thus produced displayed promising levels of anticancer activity.