One-step preparation of 1-substituted tetrahydroisoquinolines via the Pictet–Spengler reaction using zeolite catalysts

A new, environmentally friendly variation of the Pictet–Spengler reaction has been elaborated using a small pore size zeolite. The easily separable and recyclable catalyst provided high conversions and a shorter reaction time than the classical acetic acid or trifluoroacetic acid.