SYNTHESIS OF OPTICALLY-ACTIVE BIS(2-OXAZOLINES) - CRYSTAL-STRUCTURE OF A 1,2-BIS(2-OXAZOLINYL)BENZENE.ZNCL2 COMPLEX

Dinitriles (5 - 7, 12, 13) react with enantiomerically pure beta-amino alcohols (8 - 11, 17) under zinc chloride catalysis to give optically active C2-symmetric bis(oxazolines). 1,2-Bis(2-oxazolin-2-yl)benzenes 1a - e are obtained under mild reaction conditions. H-1-NMR spectroscopy indicates the formation of 1:1 complexes 23 of these compounds with ZnCl3. The energy required for a conformational interconversion of zinc dichloride complex 23e was determined by variable-temperature H-1-NMR studies. An X-ray structure analysis was performed with the substituted [1,2-bis(2-oxazolinyl)benzene]zinc dichloride complex 23a.