A Novel C3‐Symmetric Triol as Chiral Receptor for Ammonium Ions

The enantiopure C3‐symmetric syn‐benzotriborneol was efficiently obtained in an eight‐step route. Of particular interest from a synthetic point of view are the potassium tert‐butoxide promoted bromination of camphor hydrazone (4) and the observation that the protecting groups influence the syn/anti diasteroselectivity of the cyclotrimerization reaction of 12–14. Complexation studies in deuteriochloroform revealed the capability of the cyclotrimer syn‐1 to act as host for ammonium ions, and in particular, the efficient chiral recognition of the two enantiomers of (1‐phenylethyl)ammonium chloride. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)