Borane Catalysed Annulative Sulfenylation of Internal Alkynes: Towards the Synthesis and Study of Fused Heterocycles

Key Points

• The aim is to develop a borane catalyzed method for the synthesis of fused heterocycles via intramolecular cyclisation of alkynyl amines and phenols.
• Utilized B(C₆F₅)₃ as a catalyst for intramolecular cyclisations.
• Examined N-protected alkynyl amines and phenols as substrates.
• Evaluated reaction yields for the production of 5-membered heterocycles.
• Succeeded in generating 3-sulfenyl indoles with yields reaching up to 90%.
• Produced benzo[b]furans, achieving various yields across tested examples.
• Generated 16 examples of products demonstrating the catalyst's effectiveness.