A Mild and Convenient High-Yield Alternative to the Protic Acid Catalysed Pictet-Spengler Synthesis of Tetrahydroisoquinolines - Cheung, Gi K; Earle, Martyn J; Fairhurst, Robin A; Heaney, Harry; Shuhaibar, Khamis F; Eyley, Stephen C; Ince, Francis (Synlett, 1991)