Efficient Direct and Modular Stereoselective Synthesis of Highly Functionalized Tetrahydroisoquinolines and C 2-1,1′-Bitetrahydroisoquinolines
摘要:
An efficient modular stereoselective synthesis of highly functionalized tetrahydroisoquinolines and C-2-1,1'-bitetrahydroisoquinolines chiral ligands is disclosed. The synthetic methodology relies on direct stereoselective Pictet-Spengler cyclization between (S)-4-benzyloxazolidin-2-ones and various mono-and dialdehydes using inexpensive sulfuric acid as the catalyst.
Stereospecific synthesis of oxazolo[3,4-b]tetrahydroisoquinolin-3-ones, analogs of podophyllotoxin, via benzotriazole methodology
摘要:
A stereospecific synthesis of 2-azapodophyllotoxin analogues based on benzotriazole methodology is reported. Intramolecular Friedel-Crafts reactions of benzotriazole Mannich adducts 2/3b-1 afforded 5-substituted oxazolo[3,4-b]tetrahydroisoquinolines 5b-1 as pure stereoisomers. (C) 1999 Elsevier Science Ltd. All rights reserved.
An alternative and efficient method to stereoselectively synthesize oxazolo[3,4-b]tetrahydroisoquinolin-3-ones via a Pictet-Spengler reaction promoted by Lewis acid TMSOTf from readily available (S)-4-benzyl-2-oxazolidinone with various aromatic, aliphatic, and cyclic aldehydes under room temperature is described. (C) 2013 Elsevier Ltd. All rights reserved.