Synthesis of Phosphonylated and Thiolated Indenones by Manganese(III)-Mediated Addition of Phosphorus- and Sulfur-Centered Radicals to 1,3-Diarylpropynones

Phosphorus- or sulfur-centered radicals generated from the reaction of manganese(III) acetate with dialkyl phosphonates or arylthiols undergo selective additions to conjugated alkynes followed by cyclization and rearomatization to afford 2-phosphonyl- or 2-thioaryl-substituted indenones in fair to good yields.