New perspectives for boronic esters in macrocyclic chemistry

In the present contribution a tetrameric macrocyclic compound derived from 2,6-pyridinedimethanol and 3-nitrophenyl boronic acid, as well as 10 new dimeric boronates prepared from 2-salicylideneaminoethanol and different aryl boronic acids such as a 2-methylphenyl-, 3-methylphenyl-, 4-methylphenyl-, 3-methoxyphenyl-, 4-methoxyphenyl-, 3-chlorophenyl-, 4-chlorophenyl-, 3-nitrophenyl-, 3-trifluoromethylphenyl- and 4-fluorophenylboronic acid are described. The tetrameric and three of the dimeric structures have been analyzed by X-ray crystallography, and a series of parameters such as bond length, bond angles, deviation of the boron atom from the boronate mean plane and intermolecular interactions are discussed. (C) 1999 Elsevier Science S.A. All rights reserved.