The Correlation of Lewis Acidities of Silyl Triflates with Reaction Rates of Catalyzed Diels–Alder Reactions

✍ Scribed by Gerhard Hilt; Alexander Nödling

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 315 KB
• Volume: 2011
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.201101307

✦ Synopsis

Abstract

The Lewis acidity of various silyl triflates was quantified by utilizing [D~5~]pyridine as a ^2^H NMR spectroscopy probe. The chemical shifts of the ^2^H NMR signals for pyridine–silyl adducts are reported. The rate constants of silyl triflate catalyzed Diels–Alder reactions were determined by using UV/Vis spectroscopy. A correlation of the magnitude of the ^2^H NMR chemical shifts with the rate constants for most silyl triflates investigated was observed, but Me~3~SiOTf exhibits a surprisingly large deviation. Control experiments indicate that proton catalysis of the Diels–Alder reaction can be excluded.