A screening of different metal triflates as catalysts was performed to get isochromans through an oxa-Pictet- Spengler reaction. Good to high yields were obtained for various aliphatic or aromatic aldehydes and β-arylethanols. A mechanism involving catalysis by in situ liberated triflic acid to catalyse the isochroman ring formation is proposed.
Keywords: Metal triflate, oxa-Pictet-Spengler, catalysis