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.