Synthesis of atropisomeric 1-phenylpyrrole-derived amino alcohols: New chiral ligands

An efficient synthetic method has been developed for the preparation of a new family of atropisomeric amino alcohols with 1‐phenylpyrrole backbone. The synthesis is based on the different reactivities of the two carboxylic groups in optically active 1‐[2‐carboxy‐6‐(trifluoromethyl)phenyl]‐1H‐pyrrole‐2‐carboxylic acid (1). The chemical structures of the key intermediates were confirmed by spectroscopic methods and single crystal X‐ray diffraction measurements. The very first application of a new optically active amino alcohol as catalyst for the enantioselective addition of diethylzinc to benzaldehyde demonstrated the practical usefulness of atropisomeric compounds in which there are six‐atom chains between the two functional groups. Chirality 24:532–542, 2012. © 2012 Wiley Periodicals, Inc.