Concise Four‐component Synthesis of Solid‐state Fluorescent α‐Sulfenylated Enaminones

Acid chlorides, alkynes, amines, and N‐thiosuccinimides react in a consecutive four‐component alkynylation‐addition‐sulfenylation sequence to give α‐sulfenylated enaminones in good to excellent yields. The terminal sulfenylation step is catalyzed by Yb(OTf)3 and both N‐arylthiosuccinimides and N‐alkylthio succinimides can be successfully employed. Most products are solid‐state luminescent with fluorescence quantum yields up to 84% and lifetimes up to 4.9 ns. Additionally, TD‐DFT calculations rationalize the electronic structure of the absorption characteristics of the dyes.