BF₃·OEt₂‑AgSCF₃ Mediated Trifluoro­methyl­thiolation/Cascade Cyclization of Propynols: Synthesis of 4‑((Trifluoro­methyl)­thio)‑2<i>H</i>‑chromene and 4‑((Trifluoro­methyl)­thio)-1,2-dihydro­quinoline Derivatives

A BF3·OEt2–AgSCF3 mediated direct trifluoro­methyl­thiolation/cascade cyclization of propynols involving the SCF3 anion nucleophilic pathway is developed. This protocol also provides an opportunity to construct valuable trifluoromethylthio-substituted 2H-chromene and 1,2-dihydroquinoline systems with high efficiency under mild conditions. Additionally, the developed BF3·OEt2–AgSCF3 reaction system could be scaled up to gram quantities in a satisfactory yield without inert gas protection.