Concise Four‐Component Synthesis of Solid‐State Fluorescent α‐Sulfenylated Enaminones

Abstract 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.