[HEMTH]H₂[PMo₁₂O₄₀]-catalyzed oxa-Pictet–Spengler reaction of arylethanols and aldehydes to access substituted isochromans^a.

^aReaction conditions: 1 (0.6 mmol), 2 (0.66 mmol), [HEMTH]H₂[PMo₁₂O₄₀] (4 mol%), DMC (3 mL), isolated yields.