Enantiomerically pure α-pinene derivatives from material of 65% enantiomeric purity.: Part 2:: C2-symmetric N,N′-3-(2α-hydroxy)pinane diimines and diamines

The conversion of enantionterically enriched (ee > 99%) 2 alpha-hydroxypinan-3-one and its oxime (obtained in previously described procedures* from alpha-pinene of 65% ee) into a range of derivatives with potential application in asymmetric synthesis was attempted. C-2-Symmetrical compounds, ligands for potential catalysts, were synthesized from 2 alpha-hydroxypinan-3-one and either aliphatic or aromatic diamines. Reduction or etherification/reduction of selected diiminodiols afforded respective diaminodiols and diaminoethers, which were further transformed into azolium salts. Reactions of dipinanediaminoethers with dichlorophenylphosphine and subsequent in situ oxidation of the products afford the respective stable phosphinediamide oxides. Four selected compounds were crystallographically studied. (c) 2006 Elsevier Ltd. All rights reserved.