An ″α-Methylsulfone″ Transfer Agent: Synthesis and Application of γ-Ketosulfones

An operationally simple, metal-free one-pot method for the synthesis of γ-ketosulfone from ketone has been developed using aryl/alkyl sulfonyl hydrazide-formaldehyde as an ″α-methylsulfone″ transfer agent. This one-carbon elongation method, promoted by a TFA-morpholine salt, exhibits a broad substrate scope, enabling efficient, straightforward access to γ-ketosulfones from ketones. The synthetic utility of γ-ketosulfone as a masked α-methylene ketone has been explored with nucleophiles and further demonstrated in one-pot reactions with active methylene compounds, leading to cyclohexenone-fused frameworks in excellent yields.