Mild and Efficient Tunable Brønsted Acidic Ionic Liquid Catalyzed <i>O</i>-Acetylation and <i>O</i>-Trimethylsilylation with Trimethylsilyl Acetate (TMSOAc) and Hexamethyldisilazane (HMDS)

• Main Authors: Amit Ravindra Pantawane, Mayur Thul, Yi-Jyun Lin, Michelle Lin, Wesley Lin, Satyanarayana Reddy Julakanti, Hsin-Ru Wu, Shun-Yuan Luo
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Catalysts
• Subjects: tunable Brønsted acidic ionic liquid; <i>O</i>-acetylation; <i>O</i>-trimethylsilylation; recycle; trimethylsilyl acetate; HMDS
• Online Access: https://www.mdpi.com/2073-4344/11/7/825
• ISSN: 2073-4344

This report discloses a mild and efficient <i>O</i>-acetylation using easily accessible TMSOAc as a novel acetyl reagent and <i>O</i>-trimethylsilylation using HMDS for various alcohols catalyzed by tunable Brønsted acidic ionic liquids (TBAILs). Imidazolium-based TBAILs were prepared by a two-step atom-economic reaction and acidities measured by using UV-visible spectroscopy. Both protections for alcohols were accomplished at room temperature with good to excellent yields, while the products and TBAILs were separated by simple work-up for <i>O</i>-silylation and column chromatography for <i>O</i>-acetylation. Notably, with the simple post-process, TBAILs catalyst in this solvent free method easily recovered and recycled several times without significant degradation.