PPA‐SiO2 Catalyzed Multi‐component Synthesis of N‐[α‐(β‐Hydroxy‐α‐naphthyl)(benzyl)] O‐Alkyl Carbamate Derivatives

Silica‐supported polyphosphoric acid (PPA‐SiO2) was found to be an efficient catalyst for the multi‐component condensation reaction of benzaldehydes, 2‐naphthol, and methyl/benzyl carbamate to afford the corresponding N‐[α‐(β‐hydroxy‐α‐naphthyl)(benzyl)] O‐alkyl carbamate derivatives in good to excellent yields. This new approach consistently has the advantage of short reaction time, high conversions, clean reaction profiles, and simple experimental and work‐up procedures.