Preparation, conformational analysis and behaviour as chiral solvating agents of 9-anthrylpentafluorophenylmethanol enantiomers: study of the diastereomeric association Miriam P erez-Trujillo, a Albert Virgili a, * and Elies Molins b a Departament de Qu  ımica Universitat Aut onoma de Barcelona, 08193 Bellaterra, Barcelona, Spain b Institut de Ci encia dels Materials de Barcelona (CSIC), Campus de la UAB, 08193 Cerdanyola, Spain Received 11 March 2004; accepted 30 March 2004 Available online Abstract—The synthesis, structure and behaviour as chiral solvating agents of the enantiomers of 9-anthrylpentafluorophenyl- methanol is reported. Ó 2004 Elsevier Ltd. All rights reserved. 1. Introduction Several alcohols containing anthracene and trifluoro- methyl groups, such as Pirkle’s alcohol 1 or a,a 0 -bis(tri- fluoromethyl)-9,10-anthracenedimethanol, 2 which are commercially available, are used as chiral solvating agents (CSA). The presence of a bulky group, such as tert-butyl 3 or adamantyl, transmits structural rigidity that compensates for the lack of acidity in the methinic proton. The presence of the aromatic group (anthra- cene) in the structure is one of the factors that allows the CSA to differentiate between enantiomers. Its proximity and relative position to the substrate affords an impor- tant and differential magnetic influence. The per-fluoro- phenyl group has a strong electron withdrawing char- acter and its presence in the CSA could increase the zones around the enantiomers where the magnetic field of the NMR becomes modified by the presence of the anisotropic groups. The preparation of the enantiomers of 9-anthrylpentafluorophenylmethanol 1 gives us a novel CSA with new interactions and new associations that offer new possibilities for enantiodistinction. 2. Results and discussion 2.1. Preparation and characterization of 9-anthrylpenta- fluorophenylmethanol The preparation of the enantiomers of 9-anthrylpenta- fluorophenylmethanol was proposed in two ways (Scheme 1): the preparation and separation of the racemic compound and the use of enantioselective reactions to prepare each of the enantiomers directly. In both cases the starting point would be the same inter- mediate, the lithium derivative of anthracene that is obtained via reaction of 9-bromoanthracene with * Corresponding author. Tel.: +34-935812924; fax: +34-935811265; e-mail: albert.virgili@uab.es nBu-Li ether F F F F F CHO ether Li F F F F F H HO Br F F F F F O F F F F F COCl CBS reduction F F F F F H HO Swern oxidation 1 4 5 8 11 1 2 1 Scheme 1. Synthesis of 9-anthrylpentafluorophenylmethanol. 0957-4166/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.tetasy.2004.03.045 Tetrahedron: Asymmetry 15 (2004) 1615–1621 Tetrahedron: Asymmetry