Catalyst-Free Direct Hydrocarbonation of Terminal Alkynes Toward E-Alkene Substituted Stabilized Sulfoxonium Ylides.

Amide and alkene moieties are frequently found in natural products and are privileged structures in pharmaceuticals and agrochemicals. Moreover, vinyl sulfoxonium ylide can be converted into a broad range of high-value compounds, thus they have been widely employed in organic synthesis. However, the synthesis of alkene-substituted amide-sulfoxonium ylides via intermolecular hydrocarbonation of alkynes remains underexplored. This study describes the development of a high-throughput approach to provide diverse functionalized E-alkene substituted (hetero)amide-sulfoxonium ylides. The reaction occurs under mild metal-free conditions, employing amide-sulfoxonium ylides as highly effective nucleophiles, which participate in Michael addition reactions with various substituted alkynes, such as esters, thioesters, ketones, amides, and sulfones. This low-cost, operationally simple approach has a broad substrate scope, high functional group compatibility, and excellent regio- and stereoselectivity, making it suitable for the transformation of structurally complex molecules. Furthermore, the obtained stabilized sulfoxonium ylide products are directly useful for the synthesis of diverse valuable 1,5-dicarbonyl and thiabenzene 1-oxide compounds.